Demi Lovato has celebrated her 19th birthday in style. The former "Sonny with a Chance" star joined forces with Sober Is Sexy designer Hanna Beth in throwing a joint birthday party with glam rock theme at Beacher's Madhouse in Hollywood, California on Thursday (August 18) night.
"People who weren't dressed glam rock weren't admitted," a partygoer told PEOPLE. The party was alcohol free and has "an open Red Bull bar". The inside source continued to recall, "Demi mingled with everyone and was such a sweetheart. She danced on stage with Hanna Beth, drank Red Bull and danced a lot."
The "Skyscraper" singer donned a silver spiked Marco Marco shoulder dress for the bash held two days ahead of her actual birthday this Saturday. At the party, she was presented with a birthday cake and joined by celebrity guests that included Derek Hough, Tiffany Thornton and Hunter Parrish.
After the party which saw photos of her and Hanna covering the walls, Demi took to Twitter to express her gratitude. She wrote, "So much fun last night.. To all of my friends that showed up, thank you.. It meant so much to me :)" Her friend Jenna Schubart also made use of Twitter to share a picture of her posing together with the singer in their rocker costume.
In another news, Demi seemingly has made the first step to mend her friendship with ex-boyfriend Joe Jonas. On Thursday, she tweeted, "@joejonas Yayy! We won :)" as referring to their win at this year's Do Something Award for their duet "Make A Wave". In return, Joe wrote back, "Wow! @ddlovato Congrats dem! Super awesome!!"