Lil Wayne -- Chowing Down on Watermelon ... IN THE CLUB!!! (PHOTOS)

Lil Wayne found himself in the mood for some watermelon while partying in an Atlanta nightclub Sunday night ... and luckily he brought some with him.

Wayne was at the Velvet Room when he was seen taking a snack break. Weezy had a slice of watermelon in one hand ... and what appears to be a blunt in other.