Words are a wonderfully descriptive medium, but they can’t quite capture a laugh like Annette Bening’s: rich, full-throated and filled with delight. It broke out several times during our conversation, as I asked the 56-year-old actor about her new film, The Face of Love, and a career of some 30 years that includes memorable roles in The Grifters, American Beauty, Open Range and The Kids Are All Right, and which has brought her four Oscar nominations. She lives in Los Angeles with her husband, Warren Beatty, whom she met during the filming of Bugsy; the couple have four children. Among her forthcoming projects is a role in Beatty’s new and as yet untitled film.

What was it that made her laugh so much? Pure enjoyment of her life and career, I’d say – with the loudest chuckles reserved for memories of Robin Williams, who starred alongside her and Ed Harris in The Face of Love; touchingly, as she recalled his antics on set, she reverted to the present tense.

Your new film has a disturbing premise. You play a grief-stricken widow who glimpses a man the spitting image of her dead husband, tracks him down and befriends him – without telling him about the likeness. Tell us more about it.

The story of The Face of Love really started with the film-maker Arie Posin’s mother. His parents are a fascinating couple who emigrated from Russia; they were actually dissidents. They came to the United States and eventually his father passed away. Then his mother was walking down the street one day, and passed by a man who looked exactly like her husband. She had this extraordinary experience of melancholy, pleasure, exhilaration, all mixed together. And she told Arie the story of having seen this man who looked so much like her former husband that it was a revelatory experience. So that was the germ of his story.

Nikki, the character you play, takes her reaction to a similar experience to an extreme, though…

Yes, it is a leap of imagination that she does that. I found that whole idea very intriguing. It’s definitely a what-if story – what if you had lost your spouse and you saw someone who looked so much like them, and you missed your spouse. In Nikki’s case, she’s not really resolved it, or taken care to let go as much as she should of her dead husband.

Your “husband” and “not husband” are both played by Ed Harris...

Ed is such a good actor. I’d met him, and I’d seen him on the stage and in movies, obviously. That ended up to be a relationship which was extremely simpatico. He is generous and he’s a very professional guy – he comes in and knows what he wants to do. We laughed a lot. I just was crazy about him. And that of course makes it a lot easier when you’re supposed to be falling madly in love with someone. It was not hard to fall madly in love with Ed Harris! He’s a wonderful guy.

There’s an additional sadness to the film, though – the late Robin Williams plays the part of Nikki’s neighbour, who has also been bereaved. What was it like acting alongside him?

It was extraordinary. I had known him for many years. I hadn’t known him well, but I knew him and we had been friends, and we had kids at the same time, and there was a period many years ago where we saw them quite a bit.

First of all, many comedians aren’t necessarily fun. Some of them, as I’m sure you know, are quite dark and quite withdrawn, and maybe if they’re not on the stage, not a lot of fun. Well, Robin is not like that. Robin is so much fun, and he not only entertains the other actors, he entertains the entire crew. So of course, everyone’s looking forward to him coming on the set, because he just can’t help himself. He was so joyous and sweet. He was such a pleasure as an actor, and then as well just being drop-dead hilarious, everyone was screaming with laughter. I remember the camera operators barely being able to work because Robin would come in and just start on his riff. He was, of course, a great improviser.

In all sorts of situations...

I remember, one of my favourite things was years ago at the Golden Globe awards. Christine Lahti was out of the room when her award was announced, so there was this awkward moment when Chris was literally in the ladies’ room. And Robin Williams was in the audience, and he leapt up on the stage and started to entertain, and it was so wild, it was true spontaneity. And Christine, who’s a very graceful woman, she was very funny. She comes back on the stage – you can imagine, you’d feel slightly embarrassed, but she handled it with great grace. She had a towel, she wiped her hands on her towel, she handed it to Robin, he sat down and she proceeded with her thank you speech. It was a great moment, a moment that really crystallised Robin.

And he could be funny, but not do it unkindly?

That’s right, his humour never had a cost. He would satirise people, but he didn’t have that meanness in him.

Of course, it often happens that an actor’s work continues to appear after their death – James Gandolfini and Philip Seymour Hoffman are other recent examples. It’s eerie when you’re in the audience – it must be even more so as a co-star…

Absolutely, and with Robin particularly. I have friends who worked with him recently, and everyone feels that for him. He was really loved. There was a vulnerability about him that I think all performers have. Maybe some of us mask it more than others, and maybe he masked it from the public, but for those of us who knew him there was a tremendous, beautiful vulnerability to him.

He was just one of those guys: nobody ever had anything bad to say about him. And he’d had a long, complicated life in showbusiness, and known a lot of people, and went through a lot of stuff. Our hearts go out to him, and his family.

You’ve also had a long life in showbusiness, with so many significant and diverse roles.

I feel very grateful for that, and it also helps me to be in the moment, to look towards things that I want to do, and to know what I don’t want to do. It’s such a collaborative experience, whether it’s theatre or film, and that continues, I’m sure for most of us, to be the big draw. As performers, it’s that delicious immersion into the camaraderie and the intimacy with all your fellow actors and everybody that works on the film or the play.

You have a couple of other films coming up for release, including Danny Collins, which isn’t much like The Face of Love, is it?

Oh my gosh, no, it was completely different, and really great fun. Al Pacino is playing this sort of washed-up rock star, who decides to try to make amends with the son that he never knew. So he seeks him out, and the son is not at all charmed by this idea. But Pacino/Danny Collins decides he’s going to really make an effort, and checks in to a local hotel, and I’m the manager of the hotel, and so we meet and have a – I don’t know what to quite call it – a flirtation. And I had so much fun, I got to improvise, which I love to do, and I just found myself, basically, in hysterics. That was a delight, and I have to say, I got pretty giddy. I couldn’t help it!

And you’re also in The Search, by Michel Hazanavicius?

After winning for The Artist, he went out and made this film about the Chechen war, and I went and worked on that, and that was incredibly interesting. We shot it in Georgia.

Thinking of your really meaty recent roles, Nic in The Kids Are All Right, the wronged head of the household, comes to mind...

I love that character. I have a great affection for her. Usually when I’m done, it’s like going on a certain trip – you want to go, but then you’ve gone, and once you’re done you’re happy to be home. With that character, I feel love for her, and I feel like I could go on playing her.

Of course, you don’t only act on screen…

I’ve spent the last year doing plays. I did a little dream project of my own. There’s a woman named Ruth Draper, who was a great monologuist. She was an upper East Side society girl; she was part of this very cultured family, and she started performing these little characters that she was creating even as a kid, in parlours and at parties. And it began to evolve into what became an entire lifetime of creating characters and performing them live. And she became a big star.

I’d heard about her when I was in acting school – they played some of the recordings for us to teach us about text and inflection. I got the CDs 15 years ago, and started playing them in my car, thinking it’s just me having this weird fascination with this woman. And then I picked a few, and performed a one-woman show of a number of the monologues in LA.

I also thought maybe I’d take it to New York and even London. She was a big star in England, and a lot of the theatre folks in England know who she is because she was loved and revered there. But I don’t know if I’m going to keep doing it or not. I haven’t decided.

I wanted to ask you about the kinds of roles offered to actors – particularly female actors – as they age. Have you found it a problem?

I can’t really complain. I understand the larger picture of what that’s about, but I can’t complain because I’m approached with this interesting material and I’m very flattered by that. There are things I don’t like, things that I think don’t reflect the complexities of this particular stage of life, or what’s hilarious or ridiculous about it, or what is challenging or gut-wrenching about it. It’s harder to find those.

I know that for a lot of people things become very scarce, and it is different, there’s no question. Maybe it’s also just because I have this big family, and I’m not only focused on what the next role is – although that is always there, and I very much want to continue working.

You’ve got four children, two still at home, and your husband is pretty busy right now too, isn’t he?

Like most people I know, what we’re doing at this stage in our lives, is managing adolescents, young adults, and trying to keep everything going with that. And my husband made a film, so he’s in the middle of editing his film, a massive, wonderful thing and a big deal in our world. I played a small role in the film.

But acting still has new horizons to offer?

I like being a veteran, I like having this group of people that I know, that I’ve already worked with, and I have fewer illusions about the realities of making something. I’m lucky. There’s a lot out there that I’d like to do. Because of the way the technology is shifting, it’s really becoming one screen. So there are films, there are cable television shows, there’s a lot of good television now. There’s just a lot of stuff out there.

The Face of Love opens 12 December