In honor of Red Nose Day, Oscar-winning actress Julia Roberts accompanies Bear on a two-day wilderness trek to deliver lifesaving vaccines to a remote Kenyan village.

After a breathtaking repel from a helicopter, Bear and Hollywood sweetheart Vanessa Hudgens evade a boulder avalanche, summit a massive dormant volcano, and come face-to-face with a rattlesnake, which makes for a cringe-worthy dinner. Along the way, Vanessa shares insights on her meteoric rise to stardom and draws strength and determination from the memory of her late father.

Actor Joseph Gordon-Levitt tackles Kenya's unyielding terrain with Bear Grylls. Dropped into the elements from a helicopter, Joseph and Bear navigate a perilous rappel, milk a camel for needed hydration, and ascend a massive rock dome that tests Joseph's fear of heights like nothing before. As the duo battles a crocodile for the remains of a water buffalo that is their only hope for dinner, Joseph details his rise to fame and his efforts to honor the memory of his beloved brother.