Brooks Nader Goes Braless While Sporting Eye-Popping See-Through Top

Brooks Nader probably caused quite a few double takes on Friday ... when she stepped out for a date night with Gleb Savchenko in a sheer black top -- sans bra!

The model/dancer was snapped out with her "Dancing with the Stars" costar-turned-boyfriend in West Hollywood ... where the Sports Illustrated Swimsuit Issue star wore a completely see-through black top, no bra -- a blazer and a matching skirt.

Gleb looked dapper in a black bomber jacket and dark jeans -- but obviously, he was not the focus of people's attention.

The couple was snapped walking hand-in-hand while leaving the celeb-loved restaurant, Cecconi's ... with Brooks wearing a jewel on her ring finger -- but we looked into it, and it appears to be one she's been spotted wearing on her other hand before.

So, it sounds like wedding bells still aren't lined up for Brooks and Gleb -- remember, we talked to the 2 earlier this month about their relationship ... denying any engagement at the time, too.