The youngest American tennis star isn't 23-year-old Jamie Hampton or even 20-year-old Sloan Stephens.

Hampton and Stephens are promising, sure, but they're a little old. Micaela Bryan, on the other hand, hasn't even celebrated her second birthday and she's already scored a deal with Prince. Or, at least, that's what her Twitter account would lead you to believe.

Micaela, who was born on Jan. 31, 2012, has become somewhat of a phenomenon on Twitter. She's already got more than 12,000 followers, and her tweets humorously and adorably chronicle her travels with her famous father and uncle.

Micaela's Twitter following has even resulted in the creation of groupies. On a recent day at this year's U.S. Open, Micaela was spotted signing autographs in Flushing Meadows.

Autograph hounds and 12,000 Twitter followers? Not bad for a 1-year old.