Benji Madden is "madly in love" with Cameron Diaz.

The Good Charlotte rocker only stated dating the Hollywood actress a few weeks ago after being introduced to her via his twin brother Joel Madden's wife Nicole Richie, but the guitarist is already completely smitten with her.

"Benji is madly in love with Cameron, but she wants to take it slow -- he isn't her usual type. He has dated a lot of Nicole's friends in the past but Nicole really wants this one to work," an insider told the New York Post newspaper's Page Six column.

The new couple have been spotted hanging out at Cameron's house in Los Angeles as well as indulging in a mutual passion - working out at an Equinox gym.

Benji has enjoyed a string of romances with famous blondes over the years, including Nicole's former best friend Paris Hilton, Hugh Hefner's ex-girlfriend Holly Madison and Australian model Sophie Monk.

Meanwhile, the "Girls & Boys" hitmaker is also set to have a busy year professionally since he has formed a new band with his sibling called The Madden Brothers. The duo recently announced that their first album, Greetings From California, is being released on October 3 and they are already preparing for a tour and live shows.