Rothwell had never used an ear piece until she supported Justin Bieber on his UK tour.
The singer was selected to perform before the 'Sorry' hitmaker took to the stage during his 'Purpose World Tour' last year but has admitted she was so anxious because she didn't know how to manage the in-ear monitor, which blocks out sound from the audience, and was unsure whether the crowd liked her vocals or not.
Speaking to BANG Showbiz, she said: "The Justin Bieber tour was really cool and singing in front of that many people was something that was pretty new for me. It was very daunting. I'd never used in-ear monitors before that show and something was just shoved in my ear and I was handed a mic. Because you've got plugs in your ear, you can only hear the music. I think it was 16,000 people and I could tell some of them were enjoying it but the others I don't know because I couldn't hear a f***ing thing."
And, although she didn't get to meet the 23-year-old singer while she was supporting him, she believes he's not as much as a diva as people make out and is convinced he used to act up because he was forced to grow up too quickly when he shot to fame.
She said: "I saw him briefly walking down the corridor. He was strutting his stuff with all of his security guards. I think he's a teenager because he lost his teenage years. He's probably just re-living that and having a great time but I think it's tricky when you have so many people following you and you don't want to do anything because if he did the slightest thing, anyone could just twist it and make it unfair.
Rothwell will support Louise Redknapp at London's Scala on January 24.
Her new single 'Freedom' is out now.
Visit www.officialrothwell.com for more information.