Brooks Nader Exposes Nipples While Cozying Up with Model Jack Lumsden in Capri

Brooks Nader brought two special guests to lunch in Capri ... and actor Jack Lumsden looked thrilled with his front-row seat.

The "Baywatch" star hit a waterfront restaurant with Jack and some friends ... rocking a plunging black sheer dress that simply couldn't keep her nipples under wraps.

Brooks' nips repeatedly popped into view as she and Jack packed on the PDA at the table ... and he was all smiles during the revealing meal ... reveling in the fact cameras follow Brooks' every move.

The party later moved aboard a luxury yacht ... but Brooks' boobs weren't done sightseeing just yet ... and Jack wasn't done hamming it up with her.

She lounged on deck with Jack before diving into the Mediterranean for a swim ... where her nips once again came up for air.

Jack followed her into the sea after the pair stayed glued to each other aboard the yacht ... making this look like a lot more than a friendly Capri hang.

As TMZ previously reported ... Brooks was spotted totally topless earlier this week in Sardinia ... an interesting choice, considering she was with her parents and sister.