Denise Richards is seeing Nikki Sixx

Richards, 39, and Sixx, 52, “have been neighbors for years. They have a lot in common and are taking things slowly,” a source cited by Us Weekly reports.

On December 12, the couple was spotted at the Marmalade Cafe restaurant located in Calabasas, Calif. He took breakfast. “Nikki was telling stories and Denise was laughing,” a witness said.

The day before his 52nd birthday, Sixx tweeted about “a midnight rendezvous planned with a beautiful maiden.”

Sixx, a former heroin addict, has been married to two Playboy models. He also dated tattoo artist Kat Von D from 2008 to January 2010.

Richards has two daughters with Charlie Sheen: Sam, 6, and Lola, 5.