Christina Aguilera never imagined The Voice would become the ratings juggernaut it is today.
Ryan Seacrest interviewed the the 31-year-old "Your Body" singer on his KIIS-FM radio show September 14, where Aguilera admitted she once viewed the NBC hit as "kind of like a side project."
"[I thought], 'It'll keep me close to my son [Max, 4] in L.A. I don't have to travel,'" the five-time Grammy Award winner said. "Then it kind of took off, and there goes my free time!"
When she learned she'd be teaming up with fellow music stars Adam Levine, 33, Blake Shelton, 36, and Cee Lo Green, 38, in the spring 2011, however, Aguilera realized it was a no-brainer.
"We were all sort of holding hands together and jumping off the cliff saying, 'We believe in this concept.' I think [executive producer] Mark Burnett really helped us all sort of understand that this wasn't something to poke fun at people. This was about promoting true talent and supporting that. We can poke fun at each other, but you know, we're not into trying to do that to people on stage," Aguilera explained. "We four as artists know what it's like to have these tours, to go to these awards shows, what it takes to have the guts to go up there and perform, and it can be nerve-racking. We're all in support of that."
Though the mentors often butted heads in the past -- especially Aguilera and Levine -- the "Genie in a Bottle" singer said they've since learned to get along. "These guys are like my brothers at this point. It's hilarious what we do behind the scenes and then on camera. It's ruckus. It's so funny," Aguilera told Seacrest, 37. "One second me and Adam are in the back, Blake's taking a nap, and we're bored, so I take my red lipstick out and we start writing profanity on the outside of his trailer. We're like 5-year-olds."
Aguilera's new single, "Your Body," is available on iTunes September 17. The Voice airs Mondays and Tuesdays at 8 p.m. EST.