Bradley Cooper and Sienna Miller on starring in foodie film Burnt and their favourite dishes

It's in response to Sienna Miller, who's sitting next to him, being asked whether she'd like to be directed by him in the future.

While the 33-year-old actress today insists she'd "love that", Cooper - dressed in grey jeans, pale blue shirt and a navy denim jacket - is quick to remind her of a quote in which she reportedly said, "It would be a nightmare".

"No, it's not what I said!" she protests, laughing. "I gave him an enormous compliment, which he misread. Anyway..." adds a naturally made-up Miller, wearing jeans and a blue jumper.

As displayed during numerous red carpet appearances and interviews, the two are clearly good friends and enjoy ribbing one another.

Now, following their success in 2014's American Sniper, they have reunited on screen for the culinary-based Burnt, in which Cooper plays Adam Jones, a reformed chef who's attempting to earn a third Michelin star.

Whether or not Miller gives a thumbs up to her co-star's film-making abilities, the movie's director John Wells believes Cooper, who's been nominated for four Oscars (two for American Sniper and one each for American Hustle and Silver Linings Playbook), is going to make fantastic films.

"That's nice of him to say that. We'll see, we'll see. It'd be nice," notes the actor, who's rumoured to be helming Honeymoon With Harry, starring himself and Robert De Niro, who he's worked with on several projects.

Miller, on the other hand, hasn't "even thought about anything" in that sphere but says: "I like the idea of starting to make things, maybe producing a little bit.

"At the moment, between working and a child [she has a three-year-old daughter, Marlowe, with her ex Tom Sturridge] I kind of have my plate full."

Motherhood has made the actress (who was engaged to Jude Law after they appeared in 2004's Alfie together) take greater consideration before signing up to a project.

"The idea of committing to a film that I'm carrying for five months, that would be hard for me to do," acknowledges the actress, who was nominated for a Golden Globe and TV BAFTA in 2013 for the one-off drama The Girl.

"Luckily with these films, I manage to get shot in a certain amount of time and the great thing with this job, is that my daughter can come with me."

Plus, Burnt was filmed in London, where Miller is often based.

It's also where Gordon Ramsay and Marcus Wareing own restaurants.

The Michelin-starred chefs worked with the pair in preparation for the film, an experience Cooper describes as "a love event".

"Being able to attend a service at Gordon Ramsay's Hospital Road or watch Marcus Wareing's brigade is incredible," says the Philadelphia-born actor, who's dating the Russian supermodel Irina Shayk.

"The amount of pressure one puts themselves through to work in a kitchen at any level - I couldn't do it for any length of time."

Cooper worked in a kitchen between high school and college, and adds: "Luckily, I love to cook, but at this level, going for your third star and under this type of pressure? It's a rare breed that can withstand it."

So the screaming, swearing, plate smashing and general diva antics, as portrayed in the film, can be forgiven?

"I don't know whether it's diva moments. These guys have such passion and the environment is so intense and boiling hot, it's almost militant, in that everything has to be timed perfectly. If one person slips up, the entire thing is ruined. And they respect the produce and the animal that died," says Miller whose character, sous-chef Helene, is forced to apologise to a fish in one scene.

"There's a whole ton of stuff going on that people don't take into consideration, and I respect that passion."

Wareing, who acted as a consultant on the movie, has remarked: "My job was to ensure they respect the kitchens. They were cooking real food, they were dressing real plates and it had to be done the right way. I didn't care if they were actors, they had a job to do and that's to be chefs."

As Cooper stresses, "We're actually doing the cooking in the movie for better and for worse, and cutting ourselves quite a bit. It was a wonderful experience we will never forget. It bonded us."

Miller, who reveals her recent Broadway run in Cabaret is her "favourite creative experience ever", is set to appear in the thriller High-Rise with Tom Hiddleston, and The Lost City Of Z with Robert Pattinson, while Cooper reunites with Jennifer Lawrence for a fourth time in the upcoming Joy.

The Hunger Games actress recently wrote an essay on the gender pay gap, highlighting the fact she earned less than her American Hustle male co-leads, including Cooper.

In response, the actor's pledged to help his female co-stars negotiate their contracts by telling them how much he's earning.

"You know, I was just responding to a question about it, I didn't make a declaration. But the truth is it just seems like the natural thing to do," he says.

"It's such a rampant thing all over and, if we could do it in our business, maybe it will permeate. But why not have that discussion, absolutely."

As for whether Cooper and Miller will reunite a third time, they confess they don't have a project in the pipeline just yet.

"She might be a little sick of me," jokes the actor.

"I'm not at all. We'll work together again," Miller assures him. "Can you imagine if this was it? No."

Burnt is released on Friday