Maddie Ziegler -- Diamonds Are A Girl's BFF On Her 13th Bday

Maddie Ziegler just turned 13 and if you're wondering what a kid who's starred in 3 Sia music videos and a reality show gets when they reach teen-hood ... ice, as in a pair of diamond stud earrings.

Ziegler's family surprised the "Dance Moms" star with a birthday party at their family's favorite hibachi restaurant. We're told the youngster was punked by her family and friends, who all profusely apologized saying they couldn't make it out for her birthday.

But when Maddie showed up at the restaurant ... her BFFs Nia, Kendall and Mackenzie from the show all yelled SURPRISE!!! We're told 2 dozen people were in on it, even Abby Lee Miller.

After the group sang happy birthday, they took down a cheesecake. And to top it all off she also got what every other 13-year-old out there wants ... an Apple Watch.

Next stop for the youngsters ... L.A., where they'll be filming the new season of "Dance Moms."