He said: "Truth is, I was in a colder part of my career at the time. I was coming off, what was it, 'U-571'? I had to try different things. I did action movies, crime; and then I did 'Wedding Planner'. I thought, let's go see what it's like to just be light; never done that before. And then, s**t ... it made a whole bunch of money, and they came back, and offered me more."
The 42-year-old star also admits he has little respect for the characters he played in both 'How to Lose a Guy in 10 Days' and 'The Wedding Planner'.
He added: "The male is always the pawn in a romantic comedy. Come together, break up, go chase her, get her, roll credits. What woman wants that guy?"
Despite this, the Texas-born actor - who is starring in 2012 thriller 'Killer Joe' - says that he still takes humour "really seriously".
He said: "I take the comedy real seriously. There's a whole plan behind it. Even though those characters look like I'm just skating through, there's a design behind it.
"They look easy-breezy' but if you go digging too deep into the character, you sink the ship."