Simon Cowell is writing a children's book with the help of his five-year-old son Eric.

The Britain's Got Talent (BGT) creator has previously shared that he planned on writing a children's book about animals, following the birth of his son, after admitting he found most children's books "boring" and thought he "could do it better".

And in an interview with his ex-girlfriend Terri Seymour for British morning show Lorraine, he discussed his book plans with Eric.

"I am writing a book with Eric. I literally am as we talk," he shared. "We had some time together and I said, you know what I think we should write this book together and he's looking at me like, what? And then he started to get involved.

"We had such a fun time writing it. In the end, I said you know what, we just do it. I can't tell you yet (what it's about)."

The X Factor mogul also revealed he's planning to make a movie with fellow BGT judge David Walliams. The pair have a fractious onscreen relationship, but the 59-year-old conceded Walliams is the "right person" to make the movie with.

"I think you might have asked me over the years, what is my number one thing I'd love to do in my career and I always said I wanted to make an animated movie," he explained. "So a few years ago, we had an approach to make a movie about real life monkeys, who end up appearing on one of our shows because they can sing. And they become the biggest group in the world."

He continued: "I think David Walliams is going to write it. Yeah. I hate to say this but David is the most successful children's author, in fact author, in the U.K. at the moment. When I told him about the idea he was really excited. So, I think he's the right person to do it with."