It's no secret Kate Hudson likes herself a rock star.

The hot mama has a 7-year-old son, Ryder, with her ex-hubby, Black Crowes frontman Chris Robinson, and is now expecting another bundle of joy with Muse's Matthew Bellamy.

So why is Hudson's Something Borrowed costar telling us she could have yet another music man on her hands very soon?

Turns out, little Ryder is heading in the rock star direction, too!

"He seems like he's going to be a poet of some sort," Colin Egglesfield told us last night at the T-Mobile Sidekick 4G launch party in Beverly Hills. "He kind of keeps to himself. He's got that cool, edgy thing to him. He looks at you, kind of sizes you up. But yeah, I wouldn't doubt it if he became like his dad."

As for working with Hudson herself, the former Melrose Place star gushed, "She's great! She's a lot of fun. She's exactly what you'd think she was. Not only that, but she takes her work very seriously, total professional. It was cool having little Ryder running around set."