Watch What Happens When Mom Walks In On Her Teen Bodybuilder Son Flexing In A Thong

19-year-old YouTube bodybuilder, Kieran “Flex” Billen, loves showing off his incredible physique to his millions of anonymous YouTube viewers. 

The London teen was in the middle of filming a new “flex” video when his ‘mum’ barged into his room, catching her son flexing in a speedo with the camera rolling.

Watch what happened next below:

 Here are a few more videos of Kieran to whet your appetite: