Paris Hilton and Nicole Richie are already BFFs and TV co-stars. Could sister-in-laws be the next step?!

That's right, Paris is dating Nicole's baby daddy Joel Madden's twin brother Benji! (What a mouthful!) Over the past week, the odd-couple has been spotted all over Hollywood, smooching and holding hands. "They are dating for sure," an insider tells TMZ. "It was all about the timing." That's 'cause it was only recently that Benji ended his engagement with actress Sophie Monk! (Interesting side note: Sophie parodied Paris' saucy Carl's Jr. ad in Date Movie.) Still, Page Six reports that Benji's done a complete 180 in the love department, giving Paris a ring from Tiffany and telling friends that she's "the one."