Former The Voice coach Christina Aguilera surprised everyone when she made an appearance at the premiere of the singing competition's fourth season on Wednesday night.

The "Your Body" singer posted the above picture on her Twitter account, with the accompanying tweet, "Had a blast surprising @UsherRaymondIV @blakeshelton and @CarsonDaly at premiere screening of #TheVoice tonight. xo"

Aguilera has taken Season 4 of The Voice off to focus on her music career following the release of her album Lotus, but has expressed an interest in returning for Season 5, which would air in fall 2013. Her chair on the show is currently being filled by Shakira.

Many of the NBC series' former contestants also walked the red carpet at the TCL Chinese Theatre on Wednesday, including Season 1 runner-up Dia Frampton, Season 1 semifinalist Xenia Martinez, Season 2 finalist Tony Lucca, Season 2 semifinalists Jamar Rogers and Katrina Parker, and Season 3 runner-up Terry McDermott.

You can view a complete gallery from the red carpet at Big Red Chairs. The Voice premieres Monday on NBC.

(c)2013 Brittany Frederick/Big Red Chairs. Excerpts appear at Starpulse with permission. All rights reserved. No reproduction permitted. Visit my official website and follow me on Twitter at @bigredchairs.