Britney Spears in as 'X Factor' judge In this Sept. 24, 2011 file photo, singer Britney Spears performs on a stage during a concer...

Britney Spears in as 'X Factor' judge

In this Sept. 24, 2011 file photo, singer Britney Spears performs on a stage during a concert in Moscow, Russia, during her European tour. A source says she is joining Simon Cowell's singing contest as a judge on the singing competition series "The X-Factor." (AP Photo, file)

In this Sept. 24, 2011 file photo, singer Britney Spears performs on a stage during a concert in Moscow, Russia, during her European tour. A source says she is joining Simon Cowell's singing contest as a judge on the singing competition series "The X-Factor." (AP Photo, file) In this Sept. 27, 2011 file photo, singer Britney Spears performs on a stage during a concert in Kiev, Ukraine, during her European Femme Fatale Tour. A source says she is joining Simon Cowell's singing contest as a judge on the singing competition series "The X-Factor." (AP Photo/Leonid Naidiouk, file)

TV Personality Kim Kardashian, Honoree Sir Richard Branson and Singer Britney Spears attend Clive Davis and the Recording Academy's 2012 Pre-GRAMMY Gala and Salute to Industry Icons Honoring Richard Branson held at The Beverly Hilton Hotel on February 11, 2012 in Beverly Hills, California. (Photo by Larry Busacca/Getty Images For The Recording Academy)

In this Sept. 24, 2011 file photo, singer Britney Spears performs on a stage during a concert in Moscow, Russia, during her European tour. A source says she is joining Simon Cowell's singing contest as a judge on the singing competition series "The X-Factor." (AP Photo, file) In this Sept. 27, 2011 file photo, singer Britney Spears performs on a stage during a concert in Kiev, Ukraine, during her European Femme Fatale Tour. A source says she is joining Simon Cowell's singing contest as a judge on the singing competition series "The X-Factor." (AP Photo/Leonid Naidiouk, file) TV Personality Kim Kardashian, Honoree Sir Richard Branson and Singer Britney Spears attend Clive Davis and the Recording Academy's 2012 Pre-GRAMMY Gala and Salute to Industry Icons Honoring Richard Branson held at The Beverly Hilton Hotel on February 11, 2012 in Beverly Hills, California. (Photo by Larry Busacca/Getty Images For The Recording Academy) Singer Britney Spears arrives at KIIS FM's Wango Tango in Los Angeles on Saturday, May 14, 2011

Recording artist Britney Spears (R) and agent Jason Trawick attend An Evening of "Southern Style" presented by the St. Bernard Project & the Spears family at a private residence on May 11, 2011 in Beverly Hills, California. (Photo by David Livingston/Getty Images)

Britney Spears performs on stage during a concert in the Ukraine. AP

Lady Gaga, left, presents Britney Spears with the Video Vanguard award at the MTV Video Music Awards on Sunday Aug. 28, 2011, in Los Angeles. (AP Photo/Matt Sayles)

Britney Spears is coming to the rescue of Fox's "The X Factor," the singing contest in search of a ratings boost.

The Grammy-winning pop star has signed on as a judge for the show's second season, a person familiar with the deal said Thursday. The person was not authorized to publicly discuss details and spoke on condition of anonymity.

A call to Spears' publicist seeking comment was not immediately returned.

"The X Factor" debuted last fall to ratings that fell short of creator Simon Cowell's sky-high predictions. The show's slate was wiped nearly clean in January when judges Paula Abdul and Nicole Scherzinger exited along with host Steve Jones.

That left Cowell and music producer Antonio "L.A." Reid as judges on "X Factor," which is based on Cowell's hit U.K. series.

Spears signed a one-year, $15 million contract, E! News reported Wednesday, citing an unidentified source.

Fox declined to comment on Spears or other cast additions for "The X Factor."

Shock jock Howard Stern, however, didn't hold back at a news conference in New York touting his own new TV gig.

"I think Britney is going to stand there and eat a lollipop and wear a sexy outfit and I don't expect great opinions out of her. I'll tune in and see what kind of a train wreck she is," said Stern, who debuts Monday as a judge on NBC's "America's Got Talent."

Spears, 30, is a former child performer who became an international star with her 1999 debut album, "Baby One More Time." More hits followed, including "Oops!.. I Did It Again" and "Toxic," but her personal life was difficult, including rehab spells and time in a psychiatric ward.

Last fall, as she toured in support of her seventh album, the hit "Femme Fatale," she told The Associated Press in London: "I hear the older you get, the wiser you get and the more you know what you want — so hopefully it'll be a good year."

The "X Factor" job comes at a time of change. In April, her fiance, Jason Trawick, got approval from a Superior Court judge to become a co-conservator over the singer, joining her father in that role.

Earlier this year, Cowell was coy about rumors that Spears, as well as Fergie and Janet Jackson, were under consideration for the show.

He was also guarded about how "X Factor" will fare when it returns this fall. After Cowell predicted it would be a hit in its freshman outing with 20 million viewers, the show averaged around 12 million weekly viewers, which is respectable but not a blockbuster.

Melanie Amaro was the winner of the show's first season.