"The Masked Singer" returned last week with Season 9 and already, four celebrities have surprised the audience! Here's a list of celebrities who got unmasked so far.

Night Owl

Night Owl was unmasked on Wednesday. She revealed herself as Broadway actress Debbie Gibson, who is popularly known for her hits "Lost In Your Eyes" and "Shake Your Love." She sang "Fernando" by ABBA ahead of her elimination. Gibson later shared the unmasking video on her Twitter handle.

"Yes… it wasn't only in your dreams… it was me behind the #NightOwlMask!" the 52-year-old singer tweeted.

Rock Lobster

Aside from Gibson, Rock Lobster was also unmasked Wednesday. The audience learned it was none other than "America's Got Talent" judge and comedian Howie Mandel. Considering it was ABBA theme night on the show, Mandel performed "S.O.S." before his elimination.

Mustang

Country singer Sara Evans was behind the Mustang mask. The 52-year-old singer was eliminated in the first week after singing "Here I Go Again" by Whitesnake.

"I guess the cat's out of the bag... or the Mustang is out of the stable!" Evans wrote after sharing a series of photos on Twitter last week. "I had such an awesome time being a part of the masked singer Season 9 Premiere!"

Gnome

Dick Van Dyke became the first contestant to get unmasked this season after singing "When You're Smiling" by Billie Holiday. The 97-year-old Emmy award-winning actor is popularly known for his work in the 1961 sitcom "The Dick Van Dyke Show."

Following his exit, the actor shared that he knew judges would never guess his name.

"They were so surprised," he told Entertainment Weekly last week. "I stepped out and everybody's mouths dropped open. I think some people thought I was dead."

The show airs every Wednesday at 8.00 p.m. ET on the FOX network. You can also watch the show on Hulu and Fox's streaming platform, Tubi, the next day.

Nick Cannon hosts the show, while Ken Jeong, Nicole Scherzinger, Jenny McCarthy-Wahlberg, and Robin Thicke serve as judges.

The Masked Singer, Feb 5 episode: The Playoffs: Group A
Judges Ken Jeong (left) and Nicole Scherzinger (right) in an episode of "The Masked Singer." Greg Gayne/Fox