Christina Aguilera - Christina Aguilera Thrilled To Work With Billie Joe On The Voice

Fans of the show and the duo were surprised when the 21 Guns rocker agreed to help mentor Aguilera's hopefuls on the new season of the hit show, but the pop singer insists they had a blast together.

She tells RollingStone.com, "We laughed our a**es off. Oh my God, we made each other laugh."

And she admits she and Armstrong discovered they have a similar work ethic when it comes to music: "I think that sometimes pop music does get stereotyped as, 'We don't have as much control or say-so over the creative works behind the producing and what not.' (But) I specifically am an artist that's very involved in my own producing, creative and all of the efforts that go into putting together my album as an artist."

Armstrong will join Mary J. Blige and Rob Thomas as mentors on the new season of the programme.