Lexy Panterra Pregnant With First Child

Lexy Panterra will soon be welcoming her first child ... because TMZ has learned she's pregnant -- and she's got no issue showing off her growing baby bump.

Check out these pics of the star from a New York Fashion Week event Friday night ... where she wore a button-down shirt -- then popped the buttons to let her tanned tummy breathe.

We've learned Lexy is 5 months pregnant ... after marrying her mystery fiancé back in February -- another bombshell revelation. She's still keeping his ID a secret ... apparently he's a super low-key dude.

While she could just be taking it easy -- after all, she is growing a life inside her -- Lexy jumped up to perform her hit song "Girls" at the event ... getting the crowd rocking to the beat.

We broke the story about Lexy's engagement ... sharing the moment he got down on one knee in a heartfelt video last year -- while she was trying on wedding dresses. She said they'd already discussed tying the knot prior to the proposal, hence the dress shopping.

From engaged to pregnant in less than a year ... time flies when you're in love.

Congrats, Lexy!