"The Voice" Season 5 Watch 'Big Bang Theory's Kaley Cuoco sister Briana's Performance of "You and I" by Lady Gaga Here (VIDEO)

"The Voice" Season 5 continued last night with 'blind auditions' and they had a surprise celebrity appearance towards the end of the show. 

Kaley Cuoco star of "The Big Bang Theory" on CBS was on hand, but it was actually to support her little sister Briana Cuoco. 

Briana sang Lady Gaga's song "You and I" and just as entertaining as her performance was watching Kaley back stage. It was neat to see how much she cared for her sister and was pulling for her. 

Briana's performance eventually got Christina Aguilera to turn around. So she will be moving into the 'battle rounds' with Team Christina. 

The original coaches are all back for Season 5; Blake Shelton, Adam Levine, Christina Aguilera and Ceelo Green. 

What did you think of Briana Cuoco's performance?

Tune in to NBC tonight to watch the final episode of the 'blind audition' at 8/7 CST.