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.

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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.

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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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