Jessica Simpson Nixed "All-Day Drinking Binge" Before Discovering Pregnancy

Credit: Elle

Don't drink, Mommy!

Pregnant Jessica Simpson poses nude on the cover of ELLE's April issue -- and an inside shot reveals her fiance Eric Johnson kissing her enormous baby bump.

Due this spring, the singer and Fashion Star mentor, 31, tells the magazine she had a premonition about her baby-to-be -- a girl, she confirms to the mag -- while prepping for a debaucherous day with her pals.

"We were goin' to have an all-day drinking binge," she reveals. "Gonna ride our bikes, hang out. . . do naughty things. But I started feeling this overwhelming guilt. Why would I feel guilt at the idea of going out and having cocktails with my friends?"

Engaged to NFL pro Johnson since fall 2010, the star announced her pregnancy Oct. 31.

And now that they know it's a girl? "I swear, I will croak if she asks me for a pair of Nikes instead of Christian Louboutins!" she admits, laughing. "Eric is so athletic. We're gonna have this athletic girl and I won't even be able to take her shopping."