'N Sync heartthrob Justin Timberlake, 20, wants to lend a hand to his girlfriend, Britney Spears, 19. Actually, he wants to lend his singing voice. Timberlake has told Rolling Stone that he is helping Spears move beyond her hugely popular bubblegum sound in favor of something edgier. Ultimately, he says, he would like them to do a CD together, which he envisions would be "huge." Describing Spears, whom he has known since their days together on "The Mickey Mouse Club," as "the cream of the crop," Timberlake went on to tell the magazine about his proposed collaboration. "I want it to be somethin' new that they haven't heard us do, that they didn't think we could do. I feel like we still have artistic growth to show . . . It definitely would be a spectacle," he told the magazine. For now, 'N Sync is in the midst of a U.S. stadium concert tour promoting its new album, "Celebrity," which hit stores on Tuesday. (The album is the follow-up to last year's "No Strings Attached," which set a record by selling 2.4 million copies in its first week of domestic release.) 'N Sync member Chris Kirkpatrick, dismissing critiques that the band's music is "bubblegum" pop, is quoted by ABCNEWS.com about "Celebrity" as saying, "We're rockers too, we're rappers, we're hip-hop artists."