Reese Witherspoon's ex and the Mean Girls beauty together at last!

Ryan Phillippe and Amanda Seyfried are Hollywood's latest odd couple. The twosome made their first appearance at Kate Hudson's Halloween bash over the weekend... and then Amanda had a sleepover at Ryan's house afterward. Scandalous!

And when we asked the actress if she was dating the Cruel Intentions hunk? She replied coyly with, "You never know!"

Amanda Seyfried's first relationship was with Micah Alberti - Rumer Willis' most recent ex! She also briefly dated Emile Hirsch before getting together with her Mamma Mia! co-star Dominic Cooper.

As for Ryan Phillippe, the 36-year-old dad was in a relationship with Abbie Cornish following his marriage to actress Reese Witherspoon. Ryan's also been linked to Britney Spears, Nikki Reed and Scarlett Johansson, to name a few. Hmm, does this mean Amanda Seyfried is just another fling or will these two actually start dating?