Big Bang Theory star Kaley Cuoco appeared on week 2 of The Voice support her sister Briana Cuoco, an aspiring singer. Watch.

Christina Aguilera has outdone herself again.When Aguilera, 31, came out onstage during a live episode of NBC's "The Voice," she shocked viewers with her pink Afro wig accessorized with a tiara. The petite singer wore the same pink Afro that was a part of her sexy Halloween costume, with an equally attention-getting outfit for her duet with Cee-Lo Greene. Her cleavage spilled out of her print strapless dress with a floor-sweeping train for the live show on Tuesday, Nov. 13. The NBC mentor accented the look with star-spangled earrings, a black fur around her shoulders, and a white lace fan she held as she strut in her crystal-embellished thigh-high boots. The "Voice" judges performed her song "Make The World Move" from her latest seventh studio album, "Lotus." "About to #MakeTheWorldMove with @CeeLoGreen on @NBCTheVoice tonight. You better not miss it!!!" Aguilera tweeted before the show.

It is said that with great power comes great responsibility. That is clearly the case with NBC's hit singing competition "The Voice" and the rigorous touring demands of its celebrity judging panel.

Christina Aguilera is saying goodbye to "The Voice," but it wasn't easy for the singer to make the decision.