Of all the singing competition shows, none is more star-studded than “The Masked Singer.”

Once a singer is sent home, they are unmasked.

Donny Osmond placed second in Season 1 of “The Masked Singer” as The Peacock.

Nick Cannon with an unmasked Donny Osmond on ‘The Masked Singer’

One member of the Osmond family who found out the secret without being told was his grandson Truman.

“And I felt so bad, because I couldn’t tell him.

He says, ‘Grandpa, I think it’s you,’ I said, ‘We’ll find out!

The Peacock on ‘The Masked Singer’ stage

I don’t think so.'”

And the younger kids, they have no idea."

I get it because when I was doing ‘The Masked Singer,’ I couldn’t tell anyone."

Donny Osmond smiling

Donny and Debbie Osmond have been married since 1978, and the couple have five sons and 14 grandchildren.

Especially the young ones [were like], ‘Wait a minute, is that grandpa out there?’

It was kind of interesting," he explained.