The 38-year-old comedian and TV presenter came second on the ITV singing show, in which celebrities perform with their identities hidden inside costumes.
Father-of-five Manford said: “I’ve actually managed to keep it a secret from my children. So they’ve just found out at the same time as you that I’m on The Masked Singer!”
Manford has a five-year-old daughter Arnie with his partner Lucy, as well as 10-year-old twins, a 9-year-old daughter and 7-year-old son with ex-wife Catherine.
The former host of The One Show compared The Masked Singer to being a spy.
He said: “I’ve just loved this show, it’s been fabulous.
“The moment you leave the house you’re in a hoodie, a visor, you don’t speak to anyone backstage. It’s like MI5!”
And he admitted he had chosen to adopt a posh accent as part of his disguise and, “get rid of the Northern,” as he believed that might give him away.
Girls Aloud’s Nicola Roberts won the show as Queen Bee and opera star Katherine Jenkins came third as Octopus.
Other celebrities to have been unveiled on the show include hiphop star CeeLo Green who was Monster and Fox who was actress Denise Van Outen.
EastEnders actress Patsy Palmer, former Home Secretary Alan Johnson, The Darkness rocker Justin Hawkins and former England footballer Teddy Sheringham were the secret celebrities hiding inside Butterfly, Pharaoh, Chameleon and Tree.
Daisy was revealed to be US singer Kelis, Skin from Skunk Anansie turned out to be Duck and Jake Shears from Scissor Sisters was Unicorn.