The Queen guitarist has admitted his late bandmate - who tragically died in 1991 aged 45 due to complications from AIDS - would have been jealous of the group's current frontman because his voice is one ''in a billion''.
He told Yahoo: ''Freddie would love and hate him, because Adam has a real gift from God.
''It's a voice in a billion, nobody has that range, nobody that I've ever worked with, not just the range but the quality throughout the range. I've seen Adam develop just like I watched Freddie develop.''
The 71-year-old musician - who has continued the 'Bohemian Rhapsody' band's legacy alongside drummer Roger Taylor, 69 - has credited the 36-year-old former 'American Idol' star with their longevity.
He added: ''In no way does he imitate Freddie but he provides that piece of the jigsaw puzzle. It's stupendous, we would never be doing this now if it weren't for Adam.
''Sometimes I stop playing because I think 'what did he just do?' He's so free with his interpretations and it's just spine-chilling. The sound he makes and way he interprets a song.''
Adam joined the line-up after he sang with Queen during the 'American Idol' eight season finale - which saw him finish runner-up - and then joined them for an award show in Ireland.
Brian explained: ''There was something about Adam, this chemistry was instant and it was like we were already in a band with him.''
From their newest EP 'What Did You Think When You Made Me This Way', Nothing But Thieves drop the lyric video for their single 'Take This Lonely...
The Lumineers honour their friend and hero Tom Petty with a sensational cover of his 1996 song 'Walls' from the 'She's the One' soundtrack.
Watch Olly Murs get his nerd on as he blags his way into an exclusive Snoop Dogg party (where Rowan Atkinson is the bartender) in the video for their...
From 'Happy' to 'Banana Pancakes', these are soaked in positivity.
Mariah Carey is the picture of glamour in the black and white video for her brand new single 'With You'. It's the lead single from her forthcoming...
Eminem draws attention to the negative response his 2017 album 'Revival' received in the video for his latest song 'Venom'; a song recorded for the...
With the recent release of her third, very well received album 'Hunter' just behind her, Anna had plenty of relatively new songs to showcase.