Inside Julianne Hough’s 21st Birthday Bash!

"Dancing with the Stars" pro Julianne Hough partied at the Borgata Hotel Casino & Spa in Atlantic City on Saturday night to celebrate turning 21 -- and ET has all the details.

Julianne got into party mode with her close family, including her two sisters, who flew in from Nashville. After enjoying some chit-chat and room service cuisine, the birthday girl splurged on a gift for herself: black and navy LAMB high heels from Fixation at The Shoppes at The Water Club.

Later the whole group chowed down at Bobby Flay Steak in Borgata where Julianne drank a specialty cocktail made exclusively for her in honor of her bday.