Will Smith struggled to keep up with his younger co-stars on the set of 'Suicide Squad'.

Speaking at the European premiere of the movie at London's Odeon Leicester Square on Wednesday night (03.08.16), he said: "I'm 47. Do not hang out with 20-year-olds. Do not do it.

"It ruins every aspect of your 40-year-old life when you try to hang out with 20-year-olds.

"I had about six weeks on set when I was like: 'I can be 20, this is fun'. But from tattooing, to working 14-hour days and then hanging out for four hours, and parties on set... I need a nap."

'Suicide Squad' sees him reunite with his 'Focus' co-star Margot and he recently recalled being unimpressed by the blonde beauty when they first met - while she was annoyed by his tardiness.

Interviewing one another for E! News, Margot said: "When I first met you it was for the audition for 'Focus' and you were late. I'd come from Croatia and I remember being like 'Why is he late? I should be late.' "

Will retorted: "At least I was dressed for the interview. She walked into the audition and she had shoes like she'd walked through mud, shorts on, her hair wasn't done, I was like 'She doesn't want this at all.' "

But Margot insisted she had a good explanation for her unkempt appearance.

She said: "I'd lost my luggage. I'd been backpacking."

Margot also criticised Will - who has son Trey, 23, from a previous marriage, and Jaden 18, and Willow, 15, with wife Jada Pinkett Smith - for his lack of manners.

She said: "I hate it when you say 'huh?' It's rude.... Maybe I shouldn't be scolding a man that's twice my age."

Will added: "Somewhere as a child, Margot wasn't allowed to say 'Huh?', she had to say 'Pardon?'. It's a habit. She [shouts] 'It's pardon!'"