What's On TV reports that the countdown show will be the ex-Friday Night presenter's first TV appearance since leaving the BBC in July.
The star, who is a well-known toy collector, said of the three-hour show: "I've finally come to terms that I'm never really going to grow up, so I have decided to unashamedly and openly embrace my love of toys.
"We all have favourites from our childhood. Now thanks to Channel 4 we have the chance to find out which of them really are the nation's favourite toys."
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