Nikki Sixx and Denise Richards: Are They Dating?

NEW YORK (CBS) Are Denise Richards and Motley Crue bassist Nikki Sixx dating?

Romance rumors started flying after the actress and rocker were spotted having breakfast together on Sunday at a cafe in Calabasis, Calif.

Us Weekly, which reported the sighting, says the two are "quietly dating."

A source close to the pair told the magazine that Richards and Sixx "have been neighbors for years. They have a lot in common and are taking things slowly."

A witness who spotted them at Marmalade Cafe said, "Nikki was telling stories, and Denise was laughing."

E! Online reported that the two recently went out for coffee a couple of times, but a source told them "He is not her boyfriend."

Richards has two daughters with ex Charlie Sheen, and previously dated Bon Jovi guitarist Richie Sambora. Sixx has four children with ex-wives Donna D'Errico (of "Baywatch" fame) and Playboy Playmate Brandi Brant. He also dated Kat Von D from 2008 to January 2010.