Russell Brand knew he would 'change' with Katy Perry

Russell Brand knew he would "change" as soon as he saw Katy Perry.

The British funnyman – who has been dating the singer since last September – insists he always puts his fiancee first and is happy to have renounced his womanising ways.

He said: "I knew as soon as I saw her. My instinct was to change myself and not her. And that is a really positive thing.

"In the past, I would plunder my way through life, elbowing things out of the way, and I don't really compromise very much unless people want to persuade me that it's necessary.

"But with Katy, I wanted to listen to her and let her be who she is. I'd never want to do anything she didn't want. She's a whirling Catherine wheel of a person."

The 'Get Him to the Greek' star also admitted monogamy has given him a lot more free time.

He explained to Grazia magazine: "It is liberating, you get a lot more free time. I'm getting a lot more exercise, I can tell you that.

"Yoga, down the gym, table tennis."