0821_lavigne_insetAvril Lavigne, 27, and Chad Kroeger, 37, shocked everyone when they announced they’re engaged – but stranger pairings have happened in Hollywood!

Whether it’s love at first sight, or first musical collaboration, or first TV show and/or movie together -- six months with someone in the spotlight is probably comparable to years in the real world. It’s no wonder celebs are so quick to say “yes!”

As we try to wrap our heads around the surprising union of AvChad (too soon for nicknames?), we decided to take a look back at some of Tinseltown’s most surprising, even shocking, celebrity engagements.

From youngsters Miley Cyrus and Liam Hemsworth, to barely-divorced LeAnn Rimes and Eddie Cibrian, to goth rocker Marilyn Manson and Evan Rachel Wood, who's 20 years younger -- check out all of our unexpected celebrity couplings by clicking "Launch Gallery" below!