SPOILER ALERT: Details follow for Season 13, Episode 12 of “The Masked Singer,” “Semi-Finals Night,” which aired April 30 on Fox.

The case of Detective Lucky Duck was finally quacked on Wednesday’s episode of Fox’s “The Masked Singer.” Taika Waititi was the latest celebrity to be revealed on Season 13 of Fox’s “The Masked Singer,” playing the mysterious character that had popped up all season long on the show to share clues about the competition’s costumed contestants.

Lucky Duck appeared at the end of this week’s semi-finals episode, and instead of letting the show’s panelists guess his identity, he unmasked himself. And it was a familiar face for one of the show’s panelists: Waititi is husband to the show’s Rita Ora.

“Semi-Finals Night” brought together the final five contestants standing: Group A’s Coral, Group B’s Pearl and Boogie Woogie and Group C’s Mad Scientist Monster. The episode opened with the group singing “Handclap,” by Fitz and the Tantrums.

The four semi-finalists were split into two faceoffs this week, with the winners of those faceoffs automatically going to the finals.

Boogie Woogie and Pearl faced off first, with Pearl winning that round and advancing on to the finals. Then Mad Scientist Monster went opposite Coral, and Mad Scientist Monster won it and moved on. That left Boogie Woogie and Coral to battle it out in a smackdown for the third finale slot. Coral sang “Suddenly I See,” by KT Tunstall first, followed by Boogie Woogie singing “Are You Gonna Be My Girl,” by Jet.

But before that final vote, Lucky Duck brought out the “Ding Dong Keep It On” bell and announced all four would move on to next week’s finals. That’s when he unmasked, rather than one of the contestants.

Taika Waititi as Lucky Duck joins Edwin McCain as Nessy, Matthew Lawrence as Paparazzo, Erika Jayne as Yorkie, Method Man as Stud Muffin, Candace Cameron Bure as Cherry Blossom, James Van Der Beek as Griffin, Flavor Flav as Space Ranger, Sheana Shay as Bat, Aubrey O’Day as Ant, Oscar de la Hoya as Fuzzy Peas and Cedric the Entertainer as Honey Pot as the celebrities unmasked on “The Masked Singer” Season 13.

Back for Season 13 are host Nick Cannon, alongside panelists Jenny McCarthy Wahlberg, Ken Jeong, Rita Ora and Robin Thicke. Ora was at the desk for a third consecutive season to fill in for Nicole Scherzinger.

Also new: The “Crack the Case” clue cases, in which more clues are shared about the eliminated contestant. Meanwhile, back is the Golden Ear trophy is back in play for the panelists (whomever has the most correct guesses this season will win).

“The Masked Singer” Season 13 themed episodes include a tribute to franchises “Shrek” and “Ghostbusters,” as well as the Grand Ole Opry as it hits its 100th anniversary. Also on tap are a tribute to the Rat Pack and themes such as “Voices of Olympus: Unmasking of the Gods,” “Carnival,” “Boy Bands,” “Decades,” “Lucky 6,” a “Clash of the Masks” and the return of “Soundtrack of My Life.”

Masked contestants in Season 13 include Honey Pot, Space Ranger, Cherry Blossom, Coral, Fuzzy Peas, Ant, Paparazzo, Griffin, Boogie Woogie, Pearl, Bat, Yorkie, Stud Muffin, Nessy and Mad Scientist Monster.

Here were the performances on Wednesday’s Episode 12, “Semi-Finals Night”:

Boogie Woogie

Song: “Maps,” by Maroon 5

Panel guesses: Ed Sheeran, Kevin Jonas, Justin Guarini

How Boogie Woogie is connected to the panel: “Ken, you’re clearly a fan of my, as you’re one of my millions of followers. I promise when this is over, I will finally follow you back.”

Boogie Woogie voiceover: “Whoa Pearl, I’m not going anywhere! OK, you’ve got me fired up now. I’m usually happy go lucky guy, but the farther I get here, the more serious I’m becoming. I’m tapping into emotions that have been asleep for way too long. So tonight I’m coming out with an upbeat, uptempo song to bring the power of Boogie Woogie. That’s what it’s going to take.”

Boogie Woogie’s previous songs: “I Believe In a Thing Called Love,” by the Darkness; “Radioactive,” by Imagine Dragons; “Something in the Water,” by Carrie Underwood; “Golden Hour,” by Jvke

Boogie Woogie’s Previous panel guesses: Adam Lambert, Andy Samberg, Mika, Criss Angel, Neil Patrick Harris, Jason Mraz, George Clooney, Ryan Tedder, Gavin DeGraw, Josh Groban, Daniel Powter, Charlie Puth, Brandon Flowers

Pearl

Song: “You Don’t Own Me,” by Lesley Gore

Panel guesses: Kacey Musgraves, Martina McBride, Ann Wilson, Natalie Maines

How Pearl is connected to the panel: “Jenny. Not only did we walk the same carpet, but you watched me win one of my biggest awards at the AMAs.”

Pearl voiceover: Pearl: “It’s a showdown you want? I am no stranger to fighting for survival. Here, I’ve shown I can do any and all genres. And I’ve kept the panel spinning in circles. You know one thing about me is I’m not afraid to place a trail. When I first broke on the scene there weren’t many women doing what I was doing, and I thought, why not/ So I started my own movement and started opening doors for so many others. But tonight, it’s about showing Boogie Woogie the door. And believe me, it won’t be easy. But I can stand up for myself, so bye-bye Boogie Woogie!”

Previous songs: “Saving All My Love For You,” by Whitney Houston; “(Don’t Fear) The Reaper,” by Blue Oyster Cult; “Here You Come Again,” by Dolly Parton; “Conga,” by Gloria Estefan and Miami Sound Machine; “Your Love,” by The Outfield

Previous panel guesses: Regina King, Shania Twain, Joan Jett, Madonna, Melissa Etheridge, Sheryl Crow, Trisha Yearwood, Kellie Pickler, Carrie Underwood, Faith Hill, Jody Watley, Lisa Lisa, Pat Benatar, Bonnie Tyler, Winona Judd, Brandi Carlile

Coral

Song: “What Was I Made For?” by Billie Eilish

Panel guesses: Meg Donnelly, Kylee Russell, Sofia Carson, Peyton List, Hailee Steinfeld

How Coral is connected to the panel: “Rita. Your franchise and my franchise are going to make beautiful, sweet music later this year.”

Coral voiceover: “I am so pumped for a battle. I’m the youngest one left in the competition. And I’m actually one of the youngest ever to get this far. So there’s only one thing left to do, and that’s to wipe the floor with this crazy old scientist. I’m definitely still finding my sea legs in Hollywood, but being here has shown that I’m finally where I belong. Living out my pop star dreams, and that’s where I want to keep going. So my strategy tonight is to dig deep with an emotional song. Especially if I’m going to defeat this scientist of serenade.”

Previous songs: “Mad World,” by Tears for Fears; “Accidentally in Love,” by Counting Crows; “Luck Be a Lady,” by Frank Sinatra; “Ain’t It Fun,” by Paramore; “Sk8er Boi,” by Avril Lavigne

Previous panel guesses: Bebe Rexha, Carly Rae Jepsen, Sabrina Carpenter, Halsey, Anna Kendrick, Dove Cameron, Hailee Steinfeld, Lili Reinhart, Victoria Justice, Rachel Zegler, Camila Mendes, Selena Gomez, Brittany Snow, Hilary Duff, Ashley Tisdale, Nina Dobrev

Mad Scientist Monster

Song: “A Bar Song (Tipsy),” by Shaboozey

Panel guesses: Trace Adkins, Billy Ray Cyrus, Sam Hunt

How Mad Scientist Monster is connected to the panel: “Robin. Remember that Lucky Duck clue about someone stealing something from you? Well, that was me back in 2013.”

Mad Scientist Monster voiceover: “Hey, I’m not that old! Plus, with age comes experience. And believe me, I’ve been trying to train for this my whole life. As an athlete turned singer, I apply a sportsman mentality to all my performances. I’m not just cruising here, I’m working hard. Doing cardio, keeping my strength up, carbo loading. So I’m more than ready to take down this little tadpole. The probability of beating me is slim. So listen, all the respect to you Coral, but just like the Great Barrier Reef, girl, you’re in danger.”

Previous songs: “Unwell,” by Matchbox Twenty; “I Swear,” by All-4-One; “Love Yourself,” by Justin Bieber; “There’s Nothing Holdin’ Me Back,” by Shawn Mendes; “The Scientist,” by Coldplay

Previous panel guesses: Luke Combs, Luke Bryan, Blake Shelton, Alan Jackson, Tim McGraw, Keith Urban, Brad Paisley, Billy Ray Cyrus, Kenny Chesney, Trace Adkins, Gary LeVox from Rascal Flatts, Kane Brown, Jelly Roll

Watch Waititi’s reveal below:

In Season 12, Boyz II Men (as the Buffalo) won the Masked trophy, beating out Mario, as the Wasp, who was this season’s runner-up. They joined AJ Michalka as Strawberry Shortcake; Kobie Turner as Goo, Jana Kramer as Royal Knight, Bronson Arroyo as Sherlock Hound, Drake Bell as Ice King, Bethany Hamilton as Macaron, Natalie Imbruglia as Bluebell, Laverne Cox as Chess Piece, Andy Richter as Dusty Bunny, Paula Cole as Ship, Marsai Martin as Woodpecker, Yvette Nicole Brown as Showbird and John Elway as Leaf Sheep as the celebrities unmasked on “The Masked Singer” Season 12.

“The Masked Singer” comes from Fox Alternative Entertainment. Rosie Seitchik, Craig Plestis and Cannon are executive producers, while Seitchik serves as showrunner. The series is based on the South Korean format created by Mun Hwa Broadcasting Corp.