The Hot Right Now hitmaker is the newbie judge on this year's series and found the blind audition process tough.
"The blind auditions were crazy," she recalled this week, having filmed the stages in Manchester last year. "I found it really tough not knowing what was going to happen next.
“I had no idea who was going to sing or what I was going to say. I expected it to be a lot more controlled. After a while I was saying ‘I need a break’."
Rita explained: “We’d film for seven hours at a stretch. It was 50,000 times as tough as doing a gig.
“After a while I’d have rather been on stage for three hours straight than be in The Voice chair for any longer.”
The new signing to the series has proved a hit with audiences of more than 8 million having tuned in to every show so far.
And while Rita appears to have taken to the spinning red seats like a duck to water, she confessed that saying no to singers was always tough.
“In the beginning I found it so difficult as I don’t say no to people in everyday life," she told the Daily Star newspaper. “I always try to please people and make them happy, even when I know I can’t do something. So it was hard for me.
“All the singers are talented. The Voice doesn’t have joke acts – these people can sing, so it’s really a case of picking out the great ones from the good ones."
Rita added: “I’ve learned a lot about myself and the other coaches have taught me a lot too.”
The Voice UK continues Saturday nights on BBC One.
Browse pictures of Saturday night's latest show here...