Demi Lovato had a star-studded 30th birthday celebration! On Wednesday, the “Substance” songstress shared a series of pictures and videos from her party — which was attended by Paris Hilton, Paris Jackson, Kristen Stewart and lots of other guests. For the occasion, the birthday girl rocked a black mesh dress and black combat boots over red underwear. Lovato’s Instagram Stories started with an image from Alexandra’s Shipp’s Stories, which showed a set of photo booth print-outs.