"As you get older you have this natural desire to make things better, if you can, before you're gone. But, beyond that, I don't see much benefits [to ageing]," concludes Douglas.
Nobody is excluded from the cruelty of age, not even a Hollywood superstar like De Niro. "It's a given, there's nothing you can do about it, so you may as well make fun of it. "It's interesting when you walk down the street and you see younger people and they ignore you - their peripheral vision sees that you're one or two generations older than they are, so they're not interested. Otherwise, the grey hair you become a part of another class of person," he says.
"Second class!" chimes Douglas, adding, "I don't see any advantages other than you're more comfortable with yourself; you don't have to prove anything; you accept who you are. Both of us have younger children and it's nice to have the time to spend with them. Even as we're all around 70, I think we're going to see longer and longer life-spans and, with the digital age, he'll look like Raging Bull still! Inside, you feel like the child within you. I don't think there's a lot that changes, although the exterior changes a lot. That expression, youth is wasted on the young, is very true."
Described by Variety "as creaky as an arthritic hip", Last Vegas is a senior variation on The Hangover, with its own laugh-out-loud moments, finding mirth in the relentless tide of age as well as the nostalgia factor of the cast, which includes Morgan Freeman and Kevin Kline.
In the film Douglas plays a spray-tanned, highlighted lothario looking to settle down with a woman half his age. Still sporting his wedding ring on the day we meet in New York, he's been separated from Zeta-Jones since August last year. The status of the couple's 13-year marriage is the subject of almost daily scrutiny, with some tabloids reporting that he is trying to smooth troubled waters by visiting the family apartment each morning to make his kids pancakes.
"You can't take love for granted, you've got to protect it, you've got to nurture it and take care of it. When you're younger, you just take it for granted," he says somewhat wistfully.
Ask if either of them have retirement plans, and this, apparently, is more amusing than anything they've heard in a while.
"No. What are you going to do?" De Niro asks Douglas with that famous shrug.
"Retiring gives the impression that you're relieved that your job is over," suggests Douglas, "We love our jobs. It's so much fun, to make believe - you go different places; people are happy to see you; you get into good restaurants. Hopefully, I can get a table at one of Bobby's restaurants," he says in reference to De Niro's expanding culinary empire.
Movie preview
What: Last Vegas starring Michael Douglas, Robert De Niro, Morgan Freeman and Kevin Kline
When: Opens at cinemas tomorrow
- Independent