90210 hottie McCord, 21, and her Twilight vampire boyfriend Lutz, 23, constructed sand castles, tossed around a football and relaxed on lounge chairs.

All they needed to complete the Beach Blanket Bingo illusion would be several more couples line dancing to a hokey band, and Annette Funicello and Frankie Avalon running around hand in hand.

McCord seems to have gotten over Lutz allegedly kissing another woman at a party they were attending at the Shore Club over the weekend.

Alcohol seemed to be involved when Lutz was caught red...lipped by McCord kissing a woman who definitely wasn't her.

Page Six reports that McCord went ballistic.

"Annalynne was speechless," a source said. "She was noticeably upset and stormed off. Kellan followed her and was seen groveling and begging for her forgiveness and they made up."

That was easy!

Perhaps the woman had straight black hair like the wig McCord wore out on New Year's Eve and Lutz thought it was his AnnaLynne?

That's an excuse he might save for next time.

Photo Source: MavrixOnline.com