Kevin Hart pulled off his Book costume as he voluntarily unmasked himself on Wednesday’s season premiere of The Masked Singer on Fox.

The 44-year-old comedian was the last contestant during the season 11 premiere and performed as Book with a mustache, bookworm and books for feet.

In his clues, Book said his brother was a trouble-maker, held a detective’s badge, showed an open mic night sign, and said that he had made over ‘four billion dollars’ at the box office.

He also said his mission was to ‘prank one special friend.’

Book took the stage and sang So Sick by Ne-Yo, but panelist Robin Thicke, 46, immediately started laughing when he heard him.

‘I know who this is,’ said new panelist Rita Ora, 33.

The other panelist started laughing also and danced along as Book sang. The crowd chanted for him when he finished.

‘I’m pumped up,’ Book said. ‘I’m really pumped up. I’ve done a whole lot, right? I’ve done a lot. But what I’m doing right now might be my most novel experience yet. I’ve been looking forward to this. It’s all I’ve been thinking about. And the fact that I got to come out here and express myself and I’m ‘Turn it off!’ I’m just excited.’

Robin smiled as he spoke to Book.

‘There are only a few people that as soon as they start walking in the room I start smiling and laughing like this and that’s Kevin Hart,’ Robin said.

Kevin then decided he wanted to immediately get out of his Book costume.

‘Nick, I’m gone,’ Book said to host Nick Cannon, 43.

Robin, Rita, Ken Jeong, 54, and Jenny McCarthy, 51, all rushed to the stage to hug him.

‘Kevin, you are breaking the rules,’ Nick said.

‘I got you, Nick,’ Kevin said after earlier revealing he was on a prank mission.

‘What are you doing?’ Nick said.

‘You had no idea that I was coming here, Nick,’ Kevin said. ‘And guess what, Nick? It’s nothing you can do about it.’

‘That was the worst performance ever in the history of this show,’ Nick said.

‘Yeah, on purpose, Nick!’ Kevin said. ‘I performed bad on purpose!’

Nick told him that he looked stupid. Kevin, still wearing books for shoes, insisted that he did not look stupid.

‘There’s nothing stupid about me,’ Kevin said.

‘You ruined the freakin’ show,’ Nick said.

Kevin said he had pranked Nick and if he wanted to sing the song right he could have and warbled a few lines.

‘That’s still horrible,’ Nick said.

‘No, it’s not, Nick. You are horrible,’ Kevin said.

Kevin then tried to walk off the show wearing books for shoes.

The season 11 premiere opened with new panelist Rita singing Who Are You by The Who. Rita then took off her black mask and hugged the other panelists.

Goldfish, sporting a pink mohawk hairstyle and wearing a pink bedazzled dress, was the first contestant. She shared clues that included a jar of hearts and a glass slipper. Goldfish then sang Vampire by Olivia Rodrigo.

‘What an amazing voice,’ Rita said.