Simon Cowell thinks Carrie Underwood was a "good choice" to be the new judge on 'American Idol.'

It was revealed last month that the 'Before He Cheats' hitmaker will be replacing Katy Perry as a judge on the singing competition show and the music mogul - who was one of the panellists when Carrie won the fourth season of the talent contest in 2005 - is very happy for the country star.

Asked about Carrie's appointment alongside Luke Bryan and Lionel Richie, Simon told E! News: "I think it's a good choice.

"Carrie, we go back a long way. I remember her audition like it was yesterday. She was so good, she's such a sweet person."

When asked if Simon had any tips for being a judge for Carrie, Simon advised that you have to be honest with your opinions.

He added: "You just gotta say how you feel.

"It's not that difficult doing this job, I promise you. We all feel the same things and we don't agree, thank God. Otherwise, life would be boring. And just enjoy it."

Carrie recently vowed to be "honest" on the show, but also wants to be "kind" because she doesn’t want to crush the contestants' dreams.

Speaking during a surprise appearance at SiriusXM’s ‘Music Row Happy Hour in Las Vegas’, she said: "I think I can be honest and constructive, but still kind. And I think that’s the whole point, because people are coming in and it’s dreams. You’re part of somebody’s story from that moment on."

Despite her country music background, Carrie believes her career has shown enough versatility over the years for her to be credible in commenting on many other genres.

She said: “I feel like I’ve been so blessed to obviously be so rooted in country music, but I’ve been able to be a part of many other genres or music as well.

"I mean, I’ve got a song with Papa Roach right now. It’s a lot of fun.

"I like to think that I am versatile. And, hopefully, when I listen to people come and audition, I can have any lens I need to put on in terms of what music I’m thinking."