Are Cameron Diaz and Benji Madden shacking up?

People Magazine reported that "The Other Woman" actress and the Good Charlotte singer were spotted leaving Equinox gym together on Thursday in Los Angeles after attending a book launch the night before.

"They seemed very friendly," a source said about the gym outing. "And they looked like they were trying to avoid [being seen outside], but Cameron was super friendly with other people [at the gym]. She even taught a girl how to use one of the arm weight machines."

The pair has reportedly been seen spending time together, meeting up several times over the last month. The relationship is reportedly in the beginning stages but has been going on for "several weeks." A source told Us Weekly that the two are "just hanging out."

"They've spent a lot of time at Cameron's house," a source said. "Cameron seems very happy with Benji. He is the nicest guy and treats her like a lady."

Madden's sister-in-law, Nicole Richie, who is married to his twin brother Joel Madden, is reportedly responsible for their hook-up. Diaz has been friends with Richie for several years.  

"Nicole thought they'd click," the source told Us Weekly of Richie.

Diaz was previously involved with New York Yankees player Alex Rodriguez and singer Justin Timberlake. Madden has been linked to Paris Hilton, Carmen Electra, Sophie Monk and British singer Eliza Doolittle.

Do you see this relationship lasting?