The residents of Bikini Bottom are throwing SpongeBob SquarePants a huge surprise birthday party, and everyone’s invited!

In honor of Nickelodeon’s long-running animated series, “SpongeBob SquarePants,” turning 20 on July 17, after having premiered on that day in 1999, the network’s airing an hourlong special tonight with all of the classic characters, plus a few new and returning ones.

Titled “SpongeBob’s Big Birthday Blowout,” the anniversary episode is part animated, part live-action, featuring the voice actors playing human versions of their characters for the first time ever.

That’s right, fans will not only continue to hear the iconic voices coming out of the mouths of SpongeBob (Tom Kenny), Patrick (Bill Fagerbakke), Mr. Krabs (Clancy Brown), Sandy (Carolyn Lawrence), Squidward (Rodger Bumpass) and Plankton (Mr. Lawrence), but they’ll also get to put real-life faces to those voices, as well.

spongebob birthday cast The “SpongeBob SquarePants” voice actors really bring their characters to life in Nickelodeon’s part live-action special, “SpongeBob’s Big Birthday Blowout.” Photo: Nickelodeon

“Steve Hillenburg gave me the gift of a lifetime when he asked me to voice his porous alter ego, SpongeBob SquarePants,” Kenny said in a press release. “He changed my life and all of our lives. To reach the 20-year mark is a huge milestone and we wanted to celebrate by throwing a big party Bikini Bottom style.

“SpongeBob only comes up to the surface world on special occasions and this time one stop on his journey is The Trusty Slab restaurant. Stepping on the set and acting alongside my friends and fellow cast members was a true out of body experience. Fans are truly going to love it.”

Of what fans will see in the Nickelodeon special, the synopsis shares: “Patrick and SpongeBob journey to the surface world, where the duo come across a few familiar faces during lunchtime rush at The Trusty Slab restaurant,” the synopsis reveals. “Meanwhile the Bikini Bottom residents set up a surprise birthday party for SpongeBob.”

Also, David Hasselhoff, who guest-starred in “The SpongeBob SquarePants Movie” in 2004, is back once again interacting with SpongeBob and his friends as a fictionalized version of himself. Plus, Kel Mitchell (“All That”), Daniella Perkins (“Knight Squad”) and Jack Griffo (“Alexa & Katie”) will also appear in the special 2019 birthday episode.

“I experienced the world of SpongeBob first-hand when I appeared in ‘The SpongeBob SquarePants Movie,’ which was an amazing experience,” Hasselhoff said in the press release. “After making that cameo, kids around the world recognized me from the movie. How awesome to now come back to be part of the 20th anniversary special. I got to interact with Tom Kenny and SpongeBob. It also was a heartwarming tribute to Steve Hillenburg. Happy 20th SpongeBob. Hooray!!”

Celebrate the 20th anniversary of “SpongeBob SquarePants” when “SpongeBob’s Big Birthday Blowout” airs Friday on Nickelodeon at 7 p.m. EDT.