Phillip Schofield is worried about one aspect of presenting Text Santa - forgetting the names of his guests.
The presenter, 52, will spend an entire 24 hours broadcasting to the nation, in aid of the Text Santa charity appeal, on Monday, December 1.
To help him stay awake, he'll be joined by famous guests including Ant and Dec live from the jungle.
He said that there was one aspect of the charity appeal, which will see him on ITV3, as well as ITV1 and 2, that made him anxious.
Admitting he's "c**p" with names, the This Morning host said he worried that "a guest will sit down beside me and I'll think, 'Oh God - I can't remember what you're called!'."
But one thing the father-of-two isn't concerned about are calls of nature.
"With This Morning, you have to have a bladder of iron anyway," he said.
"If you can't go, you can't go and that's that. There's either time or there isn't, and if you do get to go, you've got to go really quickly."
Phillip will be relying on Amanda Holden - who is filling in for Holly Willoughby - to help him get through the final hours of the 24 hour-long stint on This Morning on December 2.
"This Morning will get the rough edge of my temper. I may be a little curt. But we all know each other very well, so they'll definitely forgive me a grumpy mood," he said.
:: Phillip Schofield will be presenting across ITV channels on Monday, December 1 in aid of Text Santa. To donate visit: www.itv.com/textsanta/donate.