Lucy, who is best known for her work in Wicked the stage musical, was guessed correctly by judge Dannii Minogue.
The musical star didn't seem all that upset to be unmasked as she excitedly jumped up and down after finally being able to show her face.
Lucy performed Bonnie Tyler's 'Total Eclipse of the Heart' on the show and revealed she has always been a fan.
"Oh! I was such a fan of the show. I did not miss one episode last year," she told host Osher Gunsberg.
"When you're behind the mask, it's so much fun 'cause you've kind of got this freedom to just have a go.
"I got to sing so many songs that I never would've thought I would've had a go at. I'm normally singing, you know, all musical theatre."
Dannii explained the clue that gave Lucy away, "What struck me from the first performance was the turned-out feet. I found a picture of Lucy Durack, who was standing exactly the way that I’ve seen you standing"
Lucy had been keeping her appearance a secret from her five-year-old daughter Polly and was excited to finally tell her everything she's been up to.
"I can't wait for my daughter, Polly, to see that it's me. Polly! Um, this is where I've been when I've been going to work!"
In reference to one of her clues which was a golf club, Lucy admitted she isn't a regular golfer, but it did reference one of the characters she played on stage.
She explained, "Look, I'm not a secret golfer, but you'll notice that the club is a wood and I played Elle Woods in Legally Blonde the musical!"
Lucy received a lot of attention last week after performing the Divinyls classic hit 'I Touch Myself'.
“Really didn't need to see a cactus touching its pot,” one person wrote on Twitter, with another saying: “I can’t believe I’m watching a cactus with boobs sing about touching themselves but here we are”.
Others agreed, writing: “I can’t wait to explain to future generations that a cactus with boobs once sang about masturbation on national TV and that that wasn’t even remotely the weirdest thing to happen in 2020.”
“I can't say "person dressed as sexy Cactus sings I Touch Myself" was on my 2020 bingo card yet here we are,” another said.
“I can’t believe we’re all watching a seductive Cactus,” a fan of the show said.
The Kitten, Bushranger, Puppet, Queen and Frillneck have yet to the unmasked.