Heather & Jack Move Back to Melrose

Heather Locklear and new/old boyfriend Jack Wagner were spotted frolicking on the beach on Sunday ... just like old friends!

Looks like the former "Melrose Place" stars have rediscovered each other after a long hiatus. Jack's marriage washed up in 2006, and Heather jettisoned David Spade just a short while ago.

Nothing like a good rerun!