The model -- who was famously married to Johnny Manziel once upon a time -- is now on Netflix's "Selling Sunset" ... and during their Season 7 premiere this week, she and the other girls were fantasizing about which famous hunk they'd love to get in the sack.

Chrishell Stause kicked off the hypothetical, asking the ladies who they'd like a go at -- to which Amanza Smith immediately answered with MBJ ... kinda a no-brainer, right?

Welp, apparently so for Bre ... who shot back right away, saying -- "I could do that -- and I've done that." Quite proudly, we might add ... and with a mouthful of chow, very casual-like.

In other words ... Bre already went around the block with Mike, or so she claims. With that said, she didn't get into details about when/where/how, etc. It's an odd pairing, no doubt -- prior to this confession, there was really no obvious connection between BT and Michael.

Of course, there was nothing on the surface between her and Nick Cannon either ... and yet, she ended up having one of his kids kinda out of the blue a year ago.

What's interesting here about this alleged hookup story is that Michael's recent ex, Lori Harvey, was also just in the middle of an old hanky-panky tale -- namely, 'Love & Hip Hop' star Prince Michael ... who claimed to have banged LH way back in the day.