Kate Hudson's four-year-old son is obsessed with her breasts.

The 'Fool's Gold' actress revealed Ryder - her son with ex-husband Chris Robinson - has developed a keen interest in the female body and is always trying to lift up her top.

She told US talk show host Conan O'Brien: "I'm working on getting him off being interested in female parts. He thinks it's hilarious when he pulls off my shirt. He's four years old!"

Kate also admits she has trouble convincing Ryder to cut his long flowing locks as he wants to look like his rocker dad Chris.

She said: "I have managed to give him a haircut, it's just incremental!"

Meanwhile, Kate has yet again refused to comment on her relationship with cycling star Lance Armstrong.

When asked about the alleged romance, Kate said: "Yeah, I try not to talk about my personal life. I think somebody told me he was going to be on this show next week. You should ask him if we're dating."

The blonde beauty - who recently split from lover Owen Wilson - recently said she is happy for people to "speculate" about the relationship, but insisted she will never discuss details of her private life.

She said: "I don't discuss my personal life. It's better to let people speculate as much as they want to speculate. Opening up only causes more problems and more words taken out of context. Everything is always misconstrued."