Credit: Trae Patton/NBC © NBC Universal, Inc. Photo: The Voice Season 6 Coaches

There’s definitely a healthy rivalry between The Voice and its main singing competition, American Idol. However, one of the current coaches on the NBC show actually appeared on the Fox series as a guest mentor. Usher appeared in the Top 10 week of Season 9 to give some pointers to the show’s hopefuls.

Chances are good you already knew that, however, if you happen to be one of the folks who played along on Viggle LIVE! during Monday night’s episode. Nearly 63 percent correctly identified Usher as the Idol defector. After him, Shakira was the second-most popular guess (21 percent). Very few people thought six-season veterans Adam Levine (9 percent) and Blake Shelton (7 percent) cut their reality show teeth on the Fox series.

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Despite the fact that Usher has appeared on both Idol and The Voice, he has expressed reservations in the past about the effect of reality competition shows on music. "The true art form of music is being lost, because it seems so easy that everyone can do it, and that it can happen overnight," he says. "Television is a lie. It can't happen overnight.”

We guess he must have seen something different that he liked in The Voice’s format!

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