Is It Love? You Decide!

Are Nick & Vanessa, Sienna & Hayden and other duos made for each other? Tell us! By Emily Fromm

SIENNA & HAYDEN

Sienna Miller and Hayden Christensen, both 24, flirted while filming Factory Girl in Louisiana (left, at a January cast party), and recently took their snuggle-fest off set: They've been spotted in Toronto, near his hometown, and in hers, London.