Demi Lovato will celebrate a milestone birthday on August 20: she'll turn 21.  And she already has a very special birthday gift in mind.

"1 of my biggest dreams, having collected Barbies since I was a kid, is to have my own Barbie," Demi tweeted.  But the singer doesn't just want a Barbie doll with a face that looks like hers.  No, she wants one with "my actual body type...Weight & height" she continued.

Then, Demi issued a call to her fans, the Lovatics, to tweet the official Barbie account and "make it happen!"  "That would be one dope 21st birthday! Hahaha," she continued. "Also, Barbie should make dolls with cellulite! After all, around 95% of ALL women have it!"

Her fans immediately sprang into action, tweeting the Barbie account with messages like, "come on give @ddlovato a barbie that is actually her body type :) show girls all over the world what healthy looks like!!" and "A Barbie that is proportional to @ddlovatowould be an amazing thing for every girl who has ever had an eating disorder."

Stay tuned...maybe Demi will get her birthday wish after all.