02/27/2012 AT 11:45 AM EST
She officially debuted her baby bump
a mere two weeks ago, but Kristin Cavallari
already has twice as much to show for it.
"My stomach literally grew double overnight!!" the expectant reality star
, 25, Tweeted Sunday
. "This belly came out of nowhere!"
Cavallari got glam to host E!'s Academy Awards
pre-show, wearing a strapless gray gathered gown and nude Christian Louboutin heels.
She and fiancé Jay Cutler
will welcome their first child
in late summer.