Hamilton won his first world championship with McLaren in 2008 and Button won the next year with Brawn GP before the team were taken over by Mercedes.
The two became teammates at McLaren between 2010 and 2012 for three seasons before Hamilton moved to the Silver Arrows in 2013 the year before their dominance of the hybrid era began from 2014.
Since then the 34-year old has won four additional drivers title and collected many race wins to put him not far behind Michael Schumacher’s records, but Button feels the dominance of the team isn’t comparable to how the sport was previously.
Button told talkSPORT: “He’s very good. We were team-mates for three years so I could see first hand how good he is. His natural ability is fantastic.
“You really can’t compare. He’s been in a team that has dominated Formula 1.
“I have loved watching F1 this year because Ferrari and Red Bull have had chances to win races and it’s been awesome to watch, but over a season the Mercedes team has been so dominant.
“He’s done a fantastic job as a driver, he’s done what’s been asked of him, but you can’t compare him to drivers of a different era. It was a different sport, even, back then.”
“I think he is the fastest driver that has ever driven an F1 car, I really do,” the Brit added.
“I think he is unbelievably fast. Previously to this year he made some mistakes, as you would expect from a young driver, but now he’s doing such a fantastic job.
“I really do think he is very special.”