The Masked Singer: Billie Jean King, 79, reveals identity after performing as Royal Hen during A Celebration of Elton John episode on Fox show

Billie Jean King was exposed after appearing as Royal Hen on Wednesday’s episode of Fox’s The Masked Singer.

The 79-year-old tennis champion competed against Hawk, Husky and Tiki during episode 10. season called Elton John Celebration.

The episode was opened by panelist Robin Thicke (46), who came on stage and performed Sir Elton’s hit song Tiny Dancer.

During her performance, Royal Hen sang Elton’s 1975 single Philadelphia Freedom, which he wrote with Bernie Taupin in honor of Billie Jean, who was part of the Philadelphia Freedoms professional tennis team.

Ken Jeong, 54, realized after the Royal Hen performance that President Obama had awarded her the Presidential Medal of Freedom and assumed she was Billie Jean.

Tennis champ: Billie Jean King exposed after appearing as Royal Hen on Wednesday's episode of Fox's The Masked Singer

Tennis champ: Billie Jean King exposed after appearing as Royal Hen on Wednesday’s episode of Fox’s The Masked Singer

Royal Hen finished in the bottom two after the vote and went up against Hawk in a Smackdown match.

Both performed unique renditions of 1976’s Don’t Go Breaking My Heart, and the panelists declared Hawke the winner.

Robin said his latest guess was that he believed Royal Hen was Gloria Steinem, 89, while Jenny McCarthy, 50, guessed it was Rita Moreno, 91, and Nicole Scherzinger, 45, guessed it was Dr. Ruth Westheimer (95).

Ken noted that the Philadelphia Freedom was about Billie Jean and stuck to his earlier assumption that Royal Hen was a tennis champion and advocated for gender equality.

“An icon in the building,” shouted host Nick Cannon, 43, as the Royal Hen removed her mask.

“It was great, but it’s so hot. I’m sweating bullets,” Billie Jean said after removing her large head covering.

Ken was delighted that he was on time and told Billie Jean that he was “honored” that she was participating.

Billie Jean said Elton wrote the song for her, but it turned out to be the Philly anthem.

Philadelphia Song: During her performance, Royal Hen sang Elton John's 1975 single Philadelphia Freedom, which he wrote with Bernie Taupin in honor of Billie Jean, who was part of the Philadelphia Freedoms professional tennis team

Philadelphia Song: During her performance, Royal Hen sang Elton John’s 1975 single Philadelphia Freedom, which he wrote with Bernie Taupin in honor of Billie Jean, who was part of the Philadelphia Freedoms professional tennis team

Correct guess: Ken Jeong, 54, realized after the Royal Hen performance that President Obama had awarded her the Presidential Medal of Freedom and assumed she was Billie Jean

Correct guess: Ken Jeong, 54, realized after the Royal Hen performance that President Obama had awarded her the Presidential Medal of Freedom and assumed she was Billie Jean

Sweating bullets: 'It was great, but it's so hot.  I'm sweating bullets,” Billie Jean said after removing her large head covering

Sweating bullets: ‘It was great, but it’s so hot. I’m sweating bullets,” Billie Jean said after removing her large head covering

Hit song: Billie Jean said Elton wrote 'Philadelphia Freedom' for her, but it turned out to be the Philly anthem

Hit song: Billie Jean said Elton wrote ‘Philadelphia Freedom’ for her, but it turned out to be the Philly anthem

“It’s so cool,” Nicole said as she looked at Billie Jean.

The show premiered Group B with four new contestants joining the competition.

Hawk entered first and won Saturday Night’s Alright (For Fighting).

The track pack for Hawk strongly hinted at rock and roll influence.

Hawke said after his performance that like Elton, he also collaborated with Miley Cyrus.

Husky was next and performed Bennie And The Jets.

The clue later consisted of a man in a rocket ship.

“Well, I jumped up on the charts and got this platinum album,” Husky explained.

Tiki impressed with his performance of Goodbye Yellow Brick Road.

Show opener: The episode was opened by panelist Robin Thicke, 46, who took to the stage to perform Sir Elton's hit Tiny Dancer

Show opener: The episode was opened by panelist Robin Thicke, 46, who took to the stage to perform Sir Elton’s hit Tiny Dancer

Panelists: Robin, Jenny McCarthy, Nicole Scherzinger and Ken dressed up for an episode of Elton John Night

Panelists: Robin, Jenny McCarthy, Nicole Scherzinger and Ken dressed up for an episode of Elton John Night

First: Hawk went first and won Saturday Night's Alright (For Fighting)

First: Hawk went first and won Saturday Night’s Alright (For Fighting)

Big Dog: Husky was up next and performed Bennie And The Jets

Big Dog: Husky was up next and performed Bennie And The Jets

Tiki time: Tiki impressed with his performance of Goodbie Yellow's Brick Road

Tiki time: Tiki impressed with his performance of Goodbie Yellow’s Brick Road

The Masked Singer will return next week with Harry Potter Night.

Season 10 of the Fox show premiered last month, and Anthony Anderson was the first to be eliminated.

Vanderpump Rules star Tom Sandoval was eliminated earlier this month on NFL Night, followed by Michael Rapaport last week on Night of the 2000s.

London-born Bishop Briggs, 31, won season nine of The Masked Singer in May as Medusa.