No, Roger Federer has not gone off the deep end, although that new beard may look like it. Instead, before taking off (and shaving it all off) for a Laver Cup promotional event with Tomas Berdych, the now 18-time Grand Slam champion filmed for Bear Grylls' NBC adventure show Running Wild.

Grylls described Federer as "A humble, fun, determined, family centered man." Although, not everything was smooth sailing.

"Just slightly upset that he beat me at mini ping-pong on the top of the cliff face! So annoying..." added Grylls.

Of course, they also played tennis, but had to improvise.

"How to get a rope up and around a tree on a cliff!? Sometimes in the wild you have to improvise! Thankfully @rogerfederer is one hell of a good shot..." said Grylls on Instagram.

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