Rap mogul Bryan 'Birdman' Williams served up a birthday treat for his daughter as she turned 16 on Saturday (01Mar14) - he had Justin Bieber serenade her in a special video message. Bria Williams celebrated her age milestone with a party at The Bath Club in Miami, Florida at the weekend and her hip-hop star father turned to his famous pals to record a surprise clip, which was played on a big screen at her bash. The footage, obtained by TMZ.com, featured shout outs from Bow Wow, Lil Wayne and Nicki Minaj, and Bieber, who also celebrated a birthday on Saturday, brought the video to a close by saying, "What's up Bri? It's Justin here. I just wanted to say Happy Birthday. I know it's your Sweet 16 so I just wanted to sing you Happy Birthday." He then showed off his vocals by crooning an a cappella version of the traditional tune for the teen. The Baby hitmaker opted for a more low-key celebration for his 20th birthday - he was joined by family members at his rented home in Atlanta, Georgia for a small gathering.