The Golden Girls star agreed to appear as herself on the forthcoming season after she was approached by the series' creator to film scenes.
But Baldwin reveals cast members weren't choosy about who they landed for a star turn - because they drew the names of potential candidates at random.
He tells Access Hollywood, “We all put names in a hat, and we took a vote, if you could have one guest star for the whole season, who would it be? And Betty White was the winner!”
And White isn't the only star lined up for a role - Fey is convinced Justin Timberlake would be an ideal choice to appear on 30 Rock.
She adds, “We should track him down. He’d be good. I’m sure he’d totally do it - he’s not busy.”