© Getty Images

Stephen Colbert - On 'The Colbert Report,' the host said, "It is so easy to forget that the week after Christmas is one of the two holiest of holidays," he said. "The other being, of course, Shark Week."

© Getty Images

Stephen Colbert - This year, he tweeted a video of himself lighting a menorah with a shark on it (a "finorah") saying "Oh blessed art thou, king of the sea, who maketh Donald Trump, strangely randy."

© Getty Images

Ashley Tisdale - The actor could barely contain her excitement when she tweeted, "2 words. SHARK WEEK. Tonight. Im so excited. I can't. Omg. Djcisjsncjjens aaaahhhhhh."

© Getty Images

Rob Lowe - The 'Parks and Recreation' actor starred in the 2014 Shark Week promo, where he tossed chum in the air while riding two great white sharks, and also coined the phrase, "So sharky."

© Getty Images

Michael Phelps - "Hmmmm #sharkweek my night is set up," the swimmer tweeted. Check out some fin-tastic facts about Shark Week here.

© Getty Images

Rainn Wilson - The comedian and 'The Office' star tweeted, "In honor of Shark Week, I'm going to eat Michael Phelps."

© Getty Images

Demi Lovato - "IT'S ALMOST SHARK WEEK!!!!!!!" the singer tweeted.

© Getty Images

Evan Rachel Wood - The 'Westworld' actor shared a wonderful mental image with the world: "Shark week!!! (me running around the kitchen) Shark Week!!!"

© Getty Images

Jimmy Fallon - An underrated musical talent, Fallon tweeted, "Swimmin' in the ocean and you see a little motion—here comes the big fin, sharky wants his din-din! #sharkrap," in honor of the special week.

© Getty Images

Conan O’Brien - The late-night host wrote, "Can't believe it's Shark Week again. It seems like yesterday I was taking down last year's Shark Week decorations."

© Getty Images

Kenneth Cole - The fashion designer isn't exactly excited. He tweeted in 2012, "@SharkWeek 25th aniv. Why have so many been so fascinated by these creatures for so long (They don't even make good handbags)?"

© Getty Images

Katy Perry - The singer is really into Shark Week, so much so that she announced she created a "Left Shark" phone case inspired by her dancer that went viral at the 2015 Superbowl.

© Getty Images

Brad Paisley - The singer is a die-hard fan of Shark Week, and he even made a video set to one of his songs! When someone tweeted that the week was a made-up holiday he jokingly replied, "Wait? It's not in the Bible?"

© Getty Images

Khloé Kardashian - You can bet that Shark Week is playing in the home of the family everyone keeps up with, according to Khloé's tweet.

© Getty Images

Justin Bieber - The pop star's friend Joe Termini was bitten by a shark in a terrifying incident, and Bieber was a little less than sensitive about it when he wrote, "Hey [Joe] it’s #SharkWeek lol."

© Getty Images

Dwayne Johnson - In honor of both Shark Week and the late Paul Walker, one of Johnson's closest friends, the actor shot a special intro for Walker's posthumous Shark Week special.

© Getty Images

Tara Reid - The 'Sharknado' star tweeted aptly, "It’s all about Shark Week!" Check out her hilarious shark education here, where she confirms whale sharks are actually not the offspring of whales and sharks. 

© Getty Images

Ellen DeGeneres - The host tweeted, "Happy Shark Week! I love a week dedicated to the ocean’s most unforgiving predators. I can say that. Some of my best friends are sharks." Check out who Americans follow most on Twitter.

© Getty Images

Jessica Biel - Take solace in knowing that Jessica Biel and Justin Timberlake also put aside time for Shark Week in their fairy-tale lives, Biel's excited tweet confirms.

© Getty Images

Leonardo DiCaprio - Are you surprised the pop culture king of conservation got in the action? He loves the "amazing animals" and wants you to "help protect great whites from extinction."

© Getty Images

Chrissy Teigen - "IT'S ALWAYS SHARK WEEK," the model wrote. Enough said. Check out some of her best tweets here.

© Getty Images

Mario Lopez - The popular host tweeted, "Shark week starts!! Diving with great whites off the island of Guadalupe is still on my bucket list…"

© Getty Images

Simone Biles - The artistic gymnast and Olympic champion knows what the most important time of year is and she wasn't afraid to tweet it: "shark week shark week shark week."

© Getty Images

Dane Cook - The comedian looked to the future of what Shark Week could produce when he tweeted, "Shark week's fun but I can't wait until we reanimate extinct dinosaurs and have them fight aliens our government's hiding."

© Getty Images

Snooki - The 'Jersey Shore' star doesn't make any plans during Shark Week, as she tweeted, "#sharkweek all night baby!" Snooki doesn't always stay in though. Check out some of her most controversial moments on the hit show here!

© Getty Images

Christina Perri - The singer experiences the same fright as many do during Shark Week. She tweeted, "#sharkweek has me like:" and included an emoji of a monkey covering its eyes.

© Getty Images

Italia Ricci - The actor made sure everyone knew she was counting down the days when she wrote, "7 days until Shark Week, everybody."

© Getty Images

Elizabeth Banks - The actor was so excited to watch sharks all week long and added that she was "counting down." 

© Getty Images

Slash - The Guns 'N' Roses guitarist tweeted, "& so begins Shark Week. iiii]; )'."

© Getty Images

Jordin Sparks - The singer tweeted, "Im actually excited to watch #Sharkzilla!!! Lol."

© Getty Images