Gwen Stefani to replace Christina Aguilera on 'The Voice'

Gwen Stefani is reportedly joining 'The Voice' as a coach, replacing Christina Aguilera. The two new Season 7 coaches are Pharell Williams and Gwen Stefani.

American singer Gwen Stefani is reportedly ready to join "The Voice" as a coach in June. Stefani will fill the Season 7 slot vacated by Christiana Aguilera, who is pregnant with her second child.

The Season 7 Voice coaching/mentoring line up will also mark the debut of Pharrell Williams ("Happy"), who will replace Cee Lo Green. The Voice coach regulars, Adam Levine and Blake Shelton, are expected to return for Season 7.

The new coaches come on board at a time when "The Voice" is drawing bigger audiences, while other similar shows, such as "American Idol," are fading.

Stefani has six albums as a member of the No Doubt band as well as recording her own solo albums. One of Stefani's biggest hits was the 2005 "Hollaback Girl," the first digital download to sell a million copies. It was co-written with Pharrell Williams. The song's inspiration was a derogatory comment by Courtney Love, who described Gwen Stefan as a "cheerleader," in a Seventeen magazine interview. While the meaning of the "Hollaback Girl" lyrics were much debated, in 2005 Peter Wood of the National Review traced the term to construction workers in the 1940s, describing a girl who would "holler back" when the men issued cat calls. In the context of the Courtney Love comment, Wood suggested that the Stefani-Williams song meant "I don't just return insults with words. I step it up."

This past week, Stefani - a mother of three sons - made a surprise appearance at the Coachella Valley Music & Arts Festival. She sang "Hollaback Girl" during Pharrell Williams' set.  Billboard Magazine speculated that this might be her coming out party for another solo album.

Stefani has not formally announced any plans for a solo comeback, but a Twitter post after the performance suggests that she enjoyed the stage return on Saturday night. "Feels good to be out of the cave #Cochella2014 @Pharrell gx," she wrote.

Or, it could be a sneak preview of what viewers will see more of during Season 7 of 'The Voice.'

Meanwhile, Pharrell Williams – a Grammy-winning, Oscar-nominated songwriter-producer-performer – is on a hot streak. "In addition to the "He just dropped his second album, G I R L, on March 3 ('Happy' is the lead song) and finished scoring The Amazing Spider-Man 2 with Hans Zimmer as part of the Magnificent Six," notes The Hollywood Reporter.

Williams "has already made a considerable impact as a mentor, drawing on an impressive track record as both a producer and performer. It is a perfect fit for The Voice as we evolve and reach for new heights with this franchise. It feels like we are welcoming an existing family member home," said Paul Telegdy, president of alternative and late night programming for NBC Entertainment.

Will the addition of Pharrell Williams and Gwen Stefani help "The Voice?"

Probably. The current round of new coaches - Usher and Shakira - have boosted the show's ratings.

In the latest ratings sweep, The Voice was the No.1 Tuesday night show with 11.6 million viewers. The show's audience numbers are up over the previous season and are surpassing those of the original singing competition blockbuster, American Idol. This past week, American Idol had just 8.4 million viewers. And Radar Online reports that this may be the last season for long-time American Idol host Ryan Seacrest.

Meanwhile, the other Fox singing competition show "X Factor" was canceled earlier this year, after three seasons.