baby

Derek Hough and his sister Julianne joined Maria Menounos and other celebrities as they attended a huge Halloween bash in Beverly Hills Friday night. Love the costumes!

The trio, wearing their best costumes, also met up with the likes of Rosie Huntington-Whiteley, Alessandra Ambrosio and Julianne's boyfriend Ryan Seacrest at the star-studded event in the hills. If only we could get a peek at what Ryan was wearing!