Kelvin Fletcher is worried he isn't "mobile enough" for "Strictly Come Dancing".
The former "Emmerdale" actor - who has been drafted in to replace Jamie Laing on the show after he pulled out with an injury - began rehearsing with his partner Oti Mabuse this week and has been left exhausted just by their warm-up session.
Speaking on Oti's Instagram Story, Kelvin said: "The warm-up this morning - I was tired after the warm-up."
When Oti said it was just a stretch, he exclaimed: "A stretch! I was shattered. And that's one thing, I need to work on my flexibility, I'm not mobile enough."
But the 35-year-old actor is enjoying getting stuck into training and thinks their first dance will be "amazing" - if he's able to pull off the moves.
He said: "It's really, really good. Really good. Like, really good," he said. "If I get it right, if I do everything that Oti wants me to do, it's going to be amazing."
While Kelvin - who has Marnie, three, and Milo, nine months, with wife Eliza - is enjoying his training, his family will always come first.
He shared a photo of his son's bottles and wrote on Instagram: "A lovely little reality check. Strictly is amazing but being a Dad and making my son's night feed is still the best job."
Oti agreed, commenting: "Goals, family always the first priority."
The actor admitted last week it had been a "surreal" few days after he was brought into the "Strictly" line up.
He said: "Is this really happening?! It's been the most surreal week of my life! I'm a massive fan of "Strictly" so it's incredible.
"I'm so happy that I can be a part of it, but at the same time it's quite bittersweet! I'm coming in on the back of Jamie's injury - I keep thinking about him! I can't imagine going through all this excitement and then having to pull out.
"My thoughts are with him - he seems like a fantastic guy and I hope he's doing OK."