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.''
With the Jonas Brothers, Westlife and Backstreet Boys getting back together recently, we should hardly be surprised that New Kids on the Block are...
Our all-time favourite Prodigy songs from their entire back catalogue.
In memory of Keith Flint, we look over at some of his iconic moments caught on camera.
If there was ever a reason for you to try something fresh and new then Poppy Ackroyd is surely it.
The New Zealand musician is a big fan of the Emerald Isle.
An exclusive interview with ambient folk artist Runah.
Are they in love or just incredible actors?
Pablo Honey was released on this day (February 22) in 1993.