The 70-year-old Queen star has heaped praise on Adam, describing him as a ''complete joy to work with'' and has even likened him to Elvis.
Roger said: ''He's a complete joy to work with. Incredible voice. Incredible professional. And a great sense of humour, which always makes it more fun for us onstage.
''I can't imagine doing it with anyone else now. He's just great. He's been a joy.''
Adam, 38, started collaborating with the iconic band back in 2011, and has since performed with them during several worldwide tours.
Roger thinks Adam has developed a unique on-stage presence over the years.
He told Rolling Stone magazine: ''He has this gift. He has this fantastic charisma on-stage, sort of this Elvis thing. It's like Camp Elvis as opposed to Camp David.
''He's just great. I can't say enough great things. He's also a great friend and a neighbour in Los Angeles.''
Meanwhile, Roger thinks he's been in a fortunate position amid the coronavirus pandemic, as he's been able to relax at his beach house in Cornwall, South West England.
Asked about his quarantine experience, Roger shared: ''I'm one of the lucky ones.
''We have a beach house down in Cornwall, which is the south-west corner of the UK. We have a lot of space there and so it wasn't so bad.
''But like for everybody, it was a strange, worrying, anxiety-filled experience. We just didn't know what was going to happen next, and we're still kind of in that position.''
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