By Matt Audilet On Friday, an NFL fan allegedly witnessed three-time Defensive Player of the Year J.J. Watt sprinting through the streets of London. “Why did I just see @JJWatt sprinting in London by Harry Potters Cursed Child?” the fan wrote. Believe it or not, Watt responded to this tweet and confirmed that it was in fact a true story. “I left my phone in the Uber and wasn’t about to be stranded in England. If there was a clock on that, it may have been sub 4.4,” he explained. “I cannot believe you witnessed that.” Watt is seemingly enjoying some well-deserved time off after his 11th NFL sea…