Nicola Peltz Stretches Out Naked in Bathtub for Steamy Instagram Post

Nicola Peltz is baring all in her most recent Instagram post ... and, we don't mean her heart and soul -- we're talking about her chest and legs!

The model shared a few photos in an Instagram post Tuesday night ... chilling on a yacht with her husband, Brooklyn Beckham, and showing off that movie star smile of hers!

Peltz also showed off what might go down below deck ... getting totally naked for a bathtub photo -- though she covered up the important pics with her clever pose.

Nicola tagged Brooklyn in that post ... seemingly indicating he flexed his photography muscles and took the pic for his better half.

She captioned the post, "best memories," followed by a series of emojis -- including a little bathtub, lest her audience forget her steamy snap.

Of course, Nicola and Brooklyn might be focusing on the good times right now because their relationship with the Beckham family ain't so good these days ... ever since our sources say they expressed dislike for Romeo Beckham's now ex-girlfriend Kim Turnbull.

Romeo and Kim are officially through ... but, we were told there was no progress in a reconciliation between the family members even after they called it quits.

We were told Brooklyn and Nicola weren't sure they wanted to open the door and let their family back in ... especially after sources told us the couple felt their fam lied publicly about them amid all the drama.