And they said it wouldn't last!

For their sixth wedding anniversary, Jennifer Lopez, 40, and Marc Anthony -- who first renewed their vows in 2008 -- are saying "I do" again at their new Hidden Hills, California, estate June 5.

PHOTOS: Stars' gorgeous wedding pics

"We realized the bets in Vegas [on whether we'd make it] stopped at five years, so we're really looking forward to this one,"  Anthony, 41, joked to Hot Stuff.

"This is a big anniversary." And the fete will be a fine affair: "They even have a gift registry," a source says.

PHOTOS: See Jennifer -- and other stars -- in bodysuits!

Hot Stuff also reports that Glee's Mark Salling and Naya Rivera are heating up off-set.

Though the pair -- whose high school characters hook up on the Fox show -- have brushed off rumors they're dating ("I think Mark's a great guy," was all Rivera, 23, would tell Us in April), a source confirms they're an item.

PHOTOS: Glee stars' high school yearbook photos

"They've been together nine months, but got serious in the last three," the insider says.

To read more juicy gossip -- including how Sarah "Fergie" Ferguson is "broke and mortified” after getting caught in a $700,000 bribery scandal -- watch the video (above) and pick up the new issue of Us Weekly, on stands now.