Paul Rudd has been tapped to narrate “Secrets of the Octopus,” the third installment of National Geographic’s “Secrets Of…” franchise. “Secrets of the Octopus” premieres on Earth Day, April 21, on Nat Geo, and then stream the next day on Hulu and Disney+. National Geographic explorer-at-large James Cameron is behind the three-part docu-series.

“It’s been an incredible journey learning about these mysterious creatures and their interconnected lives. I can’t imagine audiences won’t be as blown away with the secret lives of octopuses as I was working on this series,” Rudd said in a statement. “If you’re going to dive deep into natural history, you have to do it with National Geographic. I’m thrilled to be working with James Cameron and the Nat Geo team to deepen our connection with the ocean and all of its creatures and curiosities.”

Rudd reps the latest star to narrate a nature doc for the network, coming soon after Awkwafina narrated the recently released “A Real Bug’s Life” and Angela Bassett narrated the upcoming “Queens,” which premieres in March. Nat Geo is set to announce the news at its portion of the Television Critics Assn. press tour on Thursday.

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“As the leader in natural history storytelling, we are constantly thinking about ways to re-energize and re-invigorate how we tell these types of stories,” Tom McDonald, head of global unscripted & factual, National Geographic, told Variety exclusively. “With ‘A Real Bug’s Life,’ we gave bugs attitude by giving them a mischievous tone with clever narration from Awkwafina; In ‘Queens,’ with a female-led production team, we flipped the previously male-dominated narrative on its head, and brought a completely new feel to the genre with music and editing I have not seen before; and in the ‘Secrets Of’ franchise, we are partnered with arguably the world’s most dedicated super star conservationist in James Cameron, who always brings a unique and distinct vision to storytelling.  All of this allows us to continue to push boundaries and redefine this field for our industry.”

“Secrets of the Octopus” comes following the Emmy-winning “Secrets of the Whales,” narrated by Sigourney Weaver, and the Emmy-nominated and Critics Choice “Secrets of the Elephants,” narrated by Natalie Portman.

In this installment, “Secrets of the Octopus” looks at the creature as like “aliens on Earth: three hearts, blue blood, and the ability to squeeze through a space the size of their eyeball. Highly intelligent, octopuses can use tools, transform their bodies to mimic other animals and even communicate with different species, including us.”

In touting Rudd as the latest Nat Geo narrator, the programmer pointed to the matchmaking process in finding the right doc voice — such as Awkwafina’s raspy voice for the insects in “A Real Bug’s Life,” Bassett’s regal voice for “Queens,” Garth Brooks’ twang for “America’s National Parks,” Jeremy Renner’s resiliency for “Incredible Animal Journeys” and Michael B. Jordan’s charismatic personality for “America the Beautiful.”

In this case, iIt’s a joyful, illuminating series narrated by Paul Rudd with real warmth and humanity,” McDonald added in a statement.

Rudd recently starred in Season 3 of Hulu’s “Only Murders in the Building” and will next be seen in “Ghostbusters: Frozen Empire” and “Death of a Unicorn.”

“Secrets of the Octopus” will also be paired with a cover story in the May issue of National Geographic magazine and a companion book written by Sy Montgomery, with National Geographic photography.

Other upcoming “Secrets Of” editions will include “Secrets of the Bees” and “Secrets of the Penguins.” “Secrets of the Octopus” comes from Earthship, SeaLight Pictures and Wildstar Films. James Cameron and Maria Wilhelm; Adam Geiger and Colette Beaudry; Anwar Mamon; and Pam Caragol are executive producers.

Here’s a first look at “Secrets of the Octopus.”