Singer Danny Jones revealed that Judd is stressed after being named one of the favourites to win the BBC One dancing competition.
"I spoke to him yesterday and he said he was mentally and physically drained," Jones told the Daily Star Sunday. "He says it's exhausting and he's only just started. He's already aching a bit and he's got a bad back from one of the moves.
"He's only just started training. Harry told me he's a bit stressed about it but he doesn't really ever moan. He just gets on with it. He is extremely competitive and committed though. He won't want to lose so he's definitely in it to win it."
Addressing claims that Judd has an unfair advantage after appearing on Strictly Come Dancing for Children In Need, Jones added: "Some of the other contestants have danced before too. Harry doesn't come from a stage background so he's not an expert like people are making him out to be."
Judd has previously admitted that he doesn't want his McFly bandmates to laugh at him when performing his routines on Strictly Come Dancing.
> Strictly Come Dancing Harry Judd, Holly Valance 'don't want to be favourites'
Watch Harry Judd speak about Strictly Come Dancing below: