Stars deny being more than friends

And, speaking at the film's London premiere about the chemistry between the two stars, director Andy Tennant revealed: "At the start of filming we had to tell them to slow down."

The Hollywood pair greeted each other warmly as they worked the red carpet in Leicester Square, and while they played down rumours of an off-screen romance, they admitted they had become very close while making the film.

Butler revealed: "We have a blast together and she appreciates that Celtic manner.

"There's nothing diva-ish about her; she's very down to earth, very sure of herself and who she is, and I'm like a little kid who doesn't take myself too seriously.

"We had a fun script and a great director, so we just had to dive in, and it was a blast."

Aniston, wearing an Alexander McQueen jacket, Valentino Couture sparkling mini-dress and Jimmy Choo shoes, said of the on-screen chemistry between herself and Butler: "It's the script's fault!"

She added: "I love my Gerry.

"We just lucked out – director fantastic, Gerry fantastic, our crew, New York – you just can't go wrong."

The action comedy features Butler as a down-on-his-luck bounty hunter who is tasked with bringing in his bail-jumping ex-wife, played by Aniston.