Swiss tennis star Roger Federer was a special guest on Discovery Channel's Running Wild with Bear Grylls. In a recent interview to BBC Radio Two, the famous TV host Grylls spoke about how Federer overcame his fear.

"Roger has been a guest I have wanted to get on for a long time. He has often said: 'Look when I retire I'll do it.' But he came back really fired up after winning the Australian Open and said: 'Come on, let's do it!' I was filming out in the Swiss Alps anyway so it happened fast and his episode was a really special one," Grylls said.