Douglas, De Niro, Freeman and Kline combine for Last Vegas
Last Vegas, a comedy that has been dubbed "The Hangover for pensioners" by critics, sees four Hollywood heavyweights - Michael Douglas, Robert De Niro, Morgan Freeman and Kevin Kline - cast in the same film for the first time.
The four have six Oscar wins and nine nominations between them, plus a combined age of 281 years.
In the movie, Michael Douglas plays a lawyer who has just turned 70 and is about to marry a woman half his age.
His three best friends, who are individually facing issues like ill health, bereavement and the boredom of retirement, decide to throw him a stag party in Vegas. According to the actors, however, it wasn't the lure of Sin City that drew them in.
"They could have sent me the phone book and I would have taken the part," quips Morgan Freeman, the eldest of the quartet, at the age of 76.
"The film was a shot at doing something with the icons of my life. We've weaved in and out of each other's life, and yet working together has never come to pass until now."
The script was written six years ago but was only green-lit recently.
Director John Turteltaub believes the go-ahead was given partly because of the success of the so-called "grey pound" in cinemas over the last two years, with films like Palme d'Or winner Amour, Quartet starring Dame Maggie Smith, and The Best Exotic Marigold Hotel enjoying worldwide box office success.
"I wanted to do a movie for baby boomers which doesn't pander to them or their age group. It has to deal with real emotional, psychological issues that this generation is experiencing," explains Turteltaub.
"This generation won't go quietly. They're going to be the first that still jumps out of airplanes when they're 80 or gets married for the third time in their seventies.
"Of course, there is a time to grow up. On the other hand, there are joys we should never give up on and this movie is about the joy of a life-long friendship."
Douglas, who turns 70 years old next year, believes the audience is there for films aimed at an older generation.
"Baby boomers - those who were born post-World War II - still hold on to their film stars and want to see them at work, as we have been for the last 30 or 40 years," he says.
"The youngsters don't have those stars now, I believe. They buy into the concept of a film itself, a story, rather than the actual actors. They don't have that loyalty."
De Niro can currently be seen as a gangster in David O Russell's American Hustle and was Oscar-nominated last year for his part in Silver Linings Playbook.
He says the situation facing older male actors "is different then with older women - that is really unfortunate - but we don't get offered what we used to.
"And I suppose I wouldn't expect to be offered some parts anymore - for instance, the kind of things that Leonardo DiCaprio is playing right now. None of us expect that.
"However, there is a sufficient amount of good opportunities out there. And there's a huge audience of people from our generation that would come back to the cinema if there were movies for them, so who knows how it will work?"
"I was just in Red 2 with Helen Mirren and Bruce Willis," adds Freeman. "That's about old timers and that did very well at the box office.
"I think it's like anything in Hollywood. In the 1970s, producers suddenly realised there was a huge African-American audience out there and started making films for them. It's when they realise this will make money."
While Last Vegas has made nearly $100m (£60m) so far at the global box office, it hasn't been as critically well-received as some of the quartet's more recent films. Empire magazine, for example, called it "an unabashed old timers' fantasy".
Douglas, however, who was given the all-clear last year after suffering with throat cancer, believes it offers a message of hope that life can begin again, no matter what someone's age is.
"And hope for a career too," he adds. "Two of my favourite actors are Michael Caine and Albert Finney. They're two Brits who have mellowed like a fine wine and they are inspirational to me.
"They're both older than me and I'm looking at how they're still conducting their careers, so I'm hopeful about that."
"There's always hope," agrees De Niro. "What else do you have? Perhaps I'll live until I'm 150 years old? I hope."
Last Vegas is out in the UK on 3 January.