Pop superstar Cher had no idea how much she knew about music and performing until she appeared as a celebrity mentor on reality show The Voice and realized how influential she could be.

The Believe hitmaker has teamed up with show regular Blake Shelton to help whip his contestants into shape for pre-taped episodes of the current season five, but the veteran entertainer admits she did not expect to make such a difference to the aspiring singers' performances until she saw the results for herself.

During an appearance on morning show Live! With Kelly & Michael, she says, "I cannot tell you... how completely devoted you become to those kids... I didn't know really what I was gonna do. I didn't really have a clue.

"Someone said mentor, but I thought, 'Yeah, whatever, two days, I guess I'm gonna see some kids do stuff and give an opinion, whatever', and then all of a sudden you become involved, and you really become involved, and then you see, like I didn't realize how much I knew.

"I didn't realize that I could say something and it really would change what someone did, like something so small. There was this young girl, this really great singer, but like, she would be singing, and she would go (make a face), but the moment she did that and lost herself in her facial expressions and her hand movements, she forgot the song, so I said, 'Stick your hands in your pockets and don't ever pull 'em out.' Next time she did the song, it was like a different person, and I was only guessing! I'm only pretending I knew what I was talking about!"

Cher joins fellow mentors Miguel, Ryan Tedder and Ed Sheeran, who will be working alongside team leaders Cee Lo Green, Adam Levine and Christina Aguilera respectively.