Christopher McQuarrie says Henry Cavill was asked to sport a moustache in 'Mission: Impossible - Fallout' on a ''whim''.

The 35-year-old actor's facial hair attracted lots of attention in the run-up to the film's release and the director has revealed the story behind the moustache via his Twitter account.

A fan asked: ''@chrismcquarrie You've probably been asked this a hundred times already but was there any specific reason for Cavill's moustache? (sic)''

And Christopher replied: ''Nope. Henry had a full beard on his previous film (Nomis) and presented that look to me the day before we started shooting. We went with it on a whim. (sic)''

Christopher, 50, has also thanked fans for taking the time to watch the new 'Mission: Impossible' movie, regardless of whether they enjoyed it or not.

He wrote on the micro-blogging website: ''Thank you for all of your kinds words this weekend. And whether you liked it, hated it, couldn't care less, thanks for checking out #MissionImpossibleFallout.

''I'm headed for a much needed vacation and will be off-line for a spell. Until then, be well and stay positive. McQ (sic)''

Meanwhile, Tom Cruise recently claimed that his 'Mission: Impossible' character will never die.

The Hollywood star has portrayed IMF agent Ethan Hunt in the last six movies in the franchise and, although his stunts keep getting riskier and more challenging, he's adamant his alter ego will be sticking around for a few more films yet.

Asked if Ethan will ever get killed off, Tom replied: ''No, no. That will never happen. Never. Never.''