Brad Pitt and his youngest son, Knox, enjoyed a boys day out on Sunday. The two were all smiles as they attended the MotoGP British Grand Prix race in Silverstone, England, on August 30. Brad, who held on tightly to Knox's hand as they made their way through the event, was there to promote the release of the documentary Hitting the Apex, a film he narrated. But it definitely wasn't all work and no play for the father of six. Brad and Knox, who covered his ears with large headphones, took time out to bond and watch the race. Knox seemed to be enamored by the speed of the cars, as he was seen frequently looking up at the monitors to see what was going on. At one point, the pair also shared a sweet cuddle on the sidelines.