The project, which sees the two charities merge for the first time, will consist of a three hour show on 23 April and was launched by Lenny Henry during an appearance on The One Show on Tuesday night.
The comedian, who is a co-founder of Comic Relief, told presenters Alex Jones and Alex Scott: “Comic Relief and Children in Need, for the very first time, are merging to raise money and raise spirits in this terrible crisis.”
Promising that the night would include prize giveaways and surprise guests, Henry revealed that Kay would be joined by Catherine Tate and Gary Barlow for the charity special.
With both Comic Relief and Children in Need supporting smaller charities across the UK, Henry admitted that the current world health crisis was putting a strain on donations.
“We’ve been contacted by lots of small charities who are desperate for any financial help we can drum up. This is our way of saying to them, ‘we’ll do our best for you,’” he said.
Kay was last on our screens in the comedy Car Share, which ended in May 2018. The year before, he cancelled his tour due to "unforeseen family circumstances".
He was due to return to the stage with his new Dance For Life tour to raise money for Cancer Research UK, but he was forced to postpone it due to the coronavirus pandemic.