Mission: Impossible actor Simon Pegg has spoken of the temptation as a Hollywood star to have affairs - but slammed people who do so as "utterly stupid".
The A-lister, who has become a hot property on the big screen following years on British TV, said he is happily married to wife Maureen with whom he has a young daughter, Matilda.
"But that isn't all set in stone," he told the Mail On Sunday's Event magazine.
" I could **** that up very easily by going and having an affair with someone who is impressed by the fact I'm an actor.
"If you do that - and people do - you are stupid. You are absolutely utterly stupid because what you are doing is just giving in to a carnal desire.
"The temptation is to feel a bit pleased with yourself and flattered. You have to stop yourself. If you risk your happiness for a fleeting moment then you are an idiot."
Pegg, who plays the eponymous role in new film Hector And The Search For Happiness, said becoming a Hollywood star has made him realise what matters in life.
"So many people believe fame equates to success, equates to happiness," he said. "But you can be very famous and very miserable; or very successful and very sad."
Speaking of filming his first big blockbuster, he said: " I've never been more miserable than stuck in a hotel room when I went out to film Mission: Impossible 3.
"It was the first big Hollywood film I shot. I didn't know LA, or anybody there, and I didn't know the wasteland that is Beverly Hills.
"I knew I should be happy and I knew the fact I wasn't was something I couldn't admit... because you have got something so many people want.
"But when you attain these things you dream of from afar, it's like trying to chase the end of a rainbow. However close you get, if you think happiness is getting to the end of a rainbow, you are never going to get it."
Pegg also spoke of his close friendship with Coldplay singer Chris Martin. The pair are godfathers to each other's children.
"He's one of the most decent people I know," he said. "He has this compulsion to make other people feel better. He's someone I have a massive amount of respect for."
The Star Trek actor also stuck up for the musician's estranged wife, actress Gwyneth Paltrow.
" There is a lot of mean-spirited bull**** talked," he said.
"People make judgements when they don't know her and it's all just c***."