The Quaxsjudges were confident after hearing this masked mouse sing. 

During the season 10 kick-off of The Masked Singer, fans were greeted by a very special guest: Demi Lovato was the first celebrity revealed on the competition show. The "Confident" singer took to the stage as "Anonymouse," performing Heart's "What About Love." However, she appeared as a one-time guest ahead of the season's official premiere on Sept. 27 and is not part of the show's contestants this season.

After Demi took off her disguise, the 31-year-old revealed why she decided to make her debut on the Fox series. "I wanted to be on your show," she told host Nick Cannon during the special Sept. 8 episode, "because it seemed so fun, and it has been so fun. And I get to sing, so its the best of both worlds."

For their final guesses, panelists Jenny McCarthy Wahlberg, Nicole Scherzinger and Robin Thicke correctly guessed Anonymouse as the Camp Rock alum, while Ken Jeong thought her to be Lady Gaga. 

When asked how the three judges knew who she was, Jenny said, "That voice! There's only a couple of people a that caliber. Demi Lovato being one of those legends."

Robin added, "When you're that good, you're that good. You are one of the great voices and talents of any generation."

It was feedback that touched Demi. "Thank you so much," she told the panelists. "Your words are so kind and I took them to heart so thank you. And the energy from this audience is so great. So thank you all for having me."

And this is not the only on-screen performance from Demi fans can look forward to this week. The singer is also set to take to the stage during the 2023 MTV Video Music Awards to perform her single "Swine." The song is also nominated in two categories, including Best Pop and Video for Good. 

Throughout the night, Demi will be joined by Karol G, Måneskin and Stray Kids, who are all set to perform live from New Jersey's Prudential Center on Tuesday, Sept. 12 at 8 p.m. ET/5 p.m. PT.

For the latest breaking news updates, click here to download the E! News App