Olivia Culpo and Danny Amendola Back Together at Friend's Wedding

Olivia Culpo and Danny Amendola just can't quit each other, it seems -- they were spotted back together over the weekend, showing off major PDA ... TMZ has learned.

The recently broken up couple were very much not so at a friend's wedding Saturday in Houston, where we're told Danny was in the wedding party. Sources tell us Olivia came as Danny's date, and that they were doing lots of kissing, hugging, and hand-holding.

Keep in mind ... they split up less than 3 months ago. Olivia told Access Hollywood in March that the two had in fact gone their separate ways, and that it was fresh and hard for her to talk about. Danny was on a similar tip a few days later, offering no comment.

It appears Olivia tried the whole single thing out for a minute -- she's been spotted out on the town with her girlfriends on a number of occasions since the break up. And we're guessing Danny did the same on his end as well.