The Show Must Go On is broadcast on Monday night on ABC, with no UK airdate set just yet.
Lambert has impressed the group’s enormous fanbase with his almighty vocal talents in recent years, and in this documentary – which follows the hot success of biopic Bohemian Rhapsody – he reveals how the “loneliness” in Mercury’s songwriting shone through.
“There’s a few of them [songs] that really hit home from me,” he can be heard saying in a preview snippet, which aired on Good Morning America.
“In learning more about Freddie over the years and learning that there was definitely a loneliness there, I feel like I have enough in common with some of the things Freddie was going through.”
Brian May said of Lambert’s arrival into the fold: “It wasn’t until this young man appeared – I’d call him a gift from God. Adam.
“We didn’t ask for him, we didn’t look for him – he just turned up. And he could do everything.”
They met on the 2009 finale of American Idol, in which Lambert was competing.
May recalled: “”The American Idol people asked us to come in and play on the final competition night. So it was between Adam and this other guy [Kris Allen].
“They’re both really good singers, but there’s some kind of chemistry already between us and Adam. It was just instant.”
Lambert said of the fateful night: “Just meeting them for the first time… it was so surreal.
“I don’t even think I realized the weight of that moment until after the fact.”
Roger Taylor also speaks out in the film, saying: “When we very first met Adam, he appeared to be more of a boy.