Reese Witherspoon & Jake Gyllenhaal

TOTALLY SERIOUS
Check out their Public Displays of Commitment: Romantic Roman holidays and outings with her kids.

Prince William & Kate Middleton

READY TO WED
Britain's abuzz with rumors of a royal engagement.

John Mayer & Jennifer Aniston

HAVING FUN
Summer fling or the real thing? It's too soon to call.

Justin Timberlake & Jessica Biel

GOING STRONG
After 17 months together, they've still got the spark—she hangs with his mom and he brings her on tour.