Serena Williams and former Destiny’s Child singer Kelly Rowland are BFFs and Williams further proved it when she posted a video to her Instagram story earlier this week.A post shared by Kelly Rowland (@kellyrowland)The 39-year-old took to her Instagram stories on Tuesday to show the items that Rowland gifted her friend from her new JustFab collection. One of the pieces was a grey one-shoulder knit dress.