Leinart Locking Lips With “Laguna Beach” Lass

THE BIG LEAD spots Matt Leinart going back to the well:

Kristin Cavallari Matt Leinart

The Arizona Cardinals QB was caught in Vegas with former flame Kristin Cavallari over the weekend. The former star of MTV’s high-brow drama “Laguna Beach” was celebrating her 21st birthday at a club in Caesar’s Palace.

According to the LAS VEGAS REVIEW-JOURNAL, when Cavallari arrived at the Pure Nightclub at 1 a.m., Matt was already waiting in the VIP room with his crew, including ex-USC teammate Chauncey Washington.

Matt & Kristin - who once dated when he was with the Trojans & she was still in high school - were seen leaving together around 3:30 a.m. Probably off to find a Denny’s that’s still open.

Leinart’s latest lovelife foray could put him in the same tabloid category as Tony Romo & Tom Brady - except Matt hasn’t actually won any games.