Mel Gibson -- Caught Giving Lip

Mel Gibson's on a roll ... a week after getting up close and personal with Maria Menounos -- the actor surfaced by the beach in L.A., planting a big smooch on an unidentified woman.

The photo was snapped yesterday outside a beach house in Santa Monica.

Mel's been on a tear in the lady department recently -- sweeping Maria Menounos off her feet at her 34th birthday party last Sunday in Encino ... literally.

Mel was even spotted last month at a Victoria's Secret party in Beverly Hills -- chatting up a mystery blonde.