Thought you'd never see them back together?... One of the saddest splits in Hollywood are to REUNITE!... Book your flights to Vegas now, because things are about to get absolutely insane at Britney’s residency shows. Fifteen years after their intense, highly publicized split, Britney and Justin might be reuniting on the stage for the performance of a lifetime, reports InTouch Weekly ‘s May 2 issue. Can you even imagine? “Britney called Justin out of the blue and said she wanted him to come to Vegas and do a series of concerts with her,” a source close to the singer claims in the report. The source explains that Justin was totally “shocked” when he got the call. “At first he laughed it off, but he was definitely intrigued,” the source explains. However, the source made sure to explain that Justin has “no animosity” towards Britney, despite their nasty split in 2002 after she allegedly cheated on him. That is so great to hear, and their fans would totally freak out if th