Nicole Richie has admitted that she is responsible for Cameron Diaz's latest romance.

Sex Tape actress Cameron, 41, has been dating Good Charlotte rocker Benji Madden, 35, over the summer and the musician recently told a radio show he felt "lucky" to be with the star.

Now Nicole, 32, speaking to Watch What Happens Live, confirmed rumours that she'd set up Cameron with her brother-in-law, Us Weekly reported.

The mum-of-two was asked by a viewer whether she'd been on a double date with the pair, and if she was happy about the romance, to which she replied: "I approve of anything that's going to make Benji happy.

"I am a devoted sister-in-law," she added

Nicole, who is married to Benji's twin brother, Good Charlotte frontman Joel Madden, said: "I'm happy for anyone who is happy, and I want everyone to be surrounded with love."

When host Andy Cohen asked her if she'd set up the couple, she replied: "Yes. I'm going to take responsibility for everything!"