Hollywood star Will Smith has admitted the most dangerous thing about his new action movie was trying to keep up with the partying of actors half his age.
The Men In Black actor stars as hitman Deadshot in comic-book film Suicide Squad, which also features model Cara Delevingne, 23, and Australian actress Margot Robbie, 26.
Arriving at the European premiere of the film in London's Leicester Square, Will 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."
Members of the cast tattooed each other with the word "squad" during filming but Will said he managed to avoid the needle.
He said: "I did give one to Joel Kinnaman. If you do it in the privacy of your trailer, you don't need a licence."
The movie sees a team of imprisoned super villains released to battle Cara's character the Enchantress.
Each member of the team is heavily armed but Cara defended the use of violence at the premiere, saying: "There is a lot of violence in this movie, but to be honest I think it's more appropriate for people to use violence when there is a witch about to destroy the world than when you can just buy a gun over a counter top."
The DC Comics movie sees classic villain The Joker return to the big screen, this time embodied by Oscar winner Jared Leto.
Jared, who wore a bright-green tail coat on the pink carpet with pale pink trousers, stayed in character during the course of filming and said the role gave him a new admiration for the actors who have played him before.
He said: "I think it was always there, the idea there had been these iconic performances and I carried with me a respect for them and how brave they were."
Jared, who has previously described the late Heath Ledger's depiction of The Joker in The Dark Knight as "perfect", said : "Heath's performance was so strong you had to walk in a different direction, you had no choice, so it gave me a lot of freedom."
Fans dressed as The Joker and his lover Harley Quinn, played by Robbie, lined the carpet to catch a glimpse of stars including Cara, who sported thigh-high boots, Jay Hernandez and Jai Courtney.
Suicide Squad is released in the UK on August 5.