The singer - who is expecting twins, a boy and a girl, with husband Nick Cannon in the next few weeks - adorned her huge bump with a picture of a butterfly, and admitted she is now ready to welcome her children into the world.
Writing on her twitter page, she said: "My attempt @ festiveness on 327! For ATLITL thank u + I
U! Comin soon #dembabies! LYMA+thanx 4 making me happy:).(sic)"
However, Mariah explained she was expecting the twins to make their arrival on her birthday after she started to feel contractions, but she was later told by doctors it was just a false alarm.
She tweeted: "So #dembabies really wanted 2 celebrate w/us/share the anniversary! I started having contractions last night..went 2 the hospital "Finally they said I could come home after they got it under control but They almost came on 3/27- happy anniversary in deed!!! We have a few more weeks 2 go but- wow!!!: ) #soreadyallready!(sic)"
Meanwhile, actor-and-comedian Nick recently admitted he and Mariah are coming up with "unique" baby names for their new brood.
He said: "They won't be getting crazy names like Carburetor or something. But they're definitely unique."