Charlie Sheen Steps Out With His New Girlfriend

06/14/2006 at 03:55 PM EDT

Denise Richards isn't the only one enjoying a new relationship. Now her ex, Charlie Sheen, has a new squeeze.

Single since January, Sheen, 40, hit the Chrysalis Butterfly Ball in Los Angeles on Saturday with 28-year-old actress and real estate investor Brooke Mueller (a.k.a Brooke Allen, star of 1999's direct-to-video Witchouse).

Sheen's rep tells PEOPLE, "She's his girlfriend."

During the event, Sheen showed his gentlemanly side, putting his suit jacket around Mueller's shoulders when the evening turned chilly.

The couple's public outing comes on the heels of Richards's European vacation with her new beau, Richie Sambora.

Richards recently told Entertainment Tonight that her relationship with Sambora, 46, was "the last thing I was looking for," adding, "It's true when they say things happen when you least expect it."