Benji Madden wasn't a big fan of the 'Sex Tape'.

The 35-year-old rocker, who is dating the movie's star Cameron Diaz, was unhappy about her nude scenes and hated seeing her get intimate with co-star Jason Segel on the big screen.

A source said: ''Benji thought 'Sex Tape' was funny, but he admitted it was really tough to see her with another guy.''

The former Good Charlotte rocker wants his 42-year-old girlfriend to start pursuing more serious roles that won't make him ''squirm''.

The insider told US OK!: ''[She] thinks he's being silly but is actually touched that he'd get jealous.''

The couple recently sparked rumours they're engaged, as Cameron has been spotted wearing a new sparkly ring around Los Angeles.

A source previously claimed she has asked Benji's sister-in-law, Nicole Richie, to help her plan their nuptials, saying: ''Cam has never been a big fan of weddings, so she has no idea where to start.''

Earlier this year, Nicole, who is married to Benji's twin brother, Joel Madden, admitted she was the one who got them together.

Asked if she set them up, she previously said: ''Yes. I'm going to take responsibility for everything!''