McFly star Tom Fletcher has said he is "overwhelmed" to be debuting the stage play of his children's book, The Christmasaurus, in front of a royal audience.
The singer-turned-writer, 31, will give a first glimpse of the full show at the Royal Variety Performance at London's Hammersmith Apollo on Tuesday evening, attended by the Prince of Wales.
Speaking in full costume during rehearsals, he told the Press Association: "I am so honoured that I get to showcase it here, as it's literally the best place I could ever imagine to show it.
"It's a little bit scary that the first time I am showing anyone the songs will be in front of royalty. It's a bit overwhelming, but very exciting.
"It's the third time I've performed at the Royal Variety, first with McFly, then with McBusted, and now with Santa - it should be good fun.
"If you need someone by your side to have your back, Santa's your guy."
While still occupied with McFly, which he founded in 2003, Fletcher first unleashed his passion for dinosaurs, writing and the festive season with his 2012 children's book, The Dinosaur That Pooped Christmas, co-written with band-mate Dougie Poynter.
Explaining his journey from musician to author, he said: "I've always loved writing and have been writing kids' picture books for the last five years.
"Then this idea came out of the blue and before I knew it, I had written a novel, inspired by a song I wrote called The Christmasaurus.
"So by the end, I had written a book and a musical as well, so it felt natural to then evolve that onto the stage.
"The book is about a young boy and a very Christmassy dinosaur and an adventure they have, which features Santa, singing elves, flying reindeer and a very nasty hunter."
The Christmasaurus Live will return in full to the Hammersmith Apollo stage next year.
But this won't be the the last fans will be seeing of Fletcher's writing - or his music.
"I've got plans for many, many more books," he said. "I'll also be going back into the studio with McFly. We've been a band for 13 years and that's something that is ongoing."
Returning to his rehearsal slot for Tuesday night's show, he said: "I was walking in and just casually said hello to Robbie Williams, then went and had a chat with Santa. That's a pretty good morning."
The Royal Variety Performance 2016 will be broadcast on ITV next week.