The Top Gun star (50) spent hours meeting fans at the premiere of his new film in London's Leicester Square last night.
Jack Reacher is based on One Shot -- one of a series of best-selling novels by Lee Child -- about the eponymous former soldier turned drifter who travels the US dealing out his own brand of justice.
Cruise said: "It was easy, it was just a great character to play.
"That's kind of my life actually, you know. Making movies I'm here in London for four months and I shoot in Pittsburgh, Baton Rouge and Italy. I spend that kind of life making movies."
Child -- real name Jim Grant -- said he knew Cruise was the right man for the role when he saw him carry on with work on set despite a serious hand injury.
The author said: "He's reckless like Reacher."
Cruise's co-star Rosamund Pike (33) said she loved working with the man she described as "the greatest movie star of my lifetime".
She said: "I was on my stomach watching Top Gun aged 12 and 13 and it was very exciting to work with a guy who is still on top of his game, and into the room walks the man who created all those iconic parts and he doesn't disappoint on any level."