Brooks Nader Swims Topless With Model Jack Lumsden

Brooks Nader looks ready to star if they ever make an R-rated version of "Baywatch" ... opting to go for a swim sans bikini top!

The actress and model was spotted in all her topless glory near Positano, Italy earlier this week ... along with her sister Sarah Jane Nader and model Jack Lumsden.

Brooks and Jack went with similar ensembles ... throwing on a pair of bottoms -- and nothing up top.

While not out of the ordinary for a guy like Jack -- who also looked great BTW -- Brooks' look certainly drew some eyes ... and made more than a few jaws drop.

The pair prepared to leap into the water together at one point ... though it looks like Brooks tricked Jack ... getting him to jump in first while she cracked up -- then holding her boobs as she dove in for a dip.

Of course, we've seen a ton of Brooks' chest this week ... remember, she was having lunch with Jack in Capri this week as well -- and her nipples just wouldn't stay out of sight!