Nicole Richie admits she set up Cameron Diaz and Benji Madden

NEW YORK, July 9 (UPI) -- Nicole Richie opened up about playing matchmaker for Cameron Diaz and her brother-in-law Benji Madden during her appearance on Watch What Happens Live Tuesday.

Richie, who was sporting her newly dyed blue hair during the show, told host Andy Cohen she took "responsibility for everything" when asked if she had been the one to set up the new couple.

As for whether or not she'd be willing to go on a double date with the pair, Richie, 32, said she "[approves] of anything that's going to make Benji happy."

"I am a devoted sister-in-law," she continued -- Richie is married to Benji's twin brother Joel Madden. "I'm happy for anyone who is happy, and I want everyone to be surrounded with love."

News of Diaz's relationship to Madden was first reported in May as the two had reportedly been "hanging out" a lot over the past few weeks.