Charlton, who scored 49 goals in 106 appearances for England, was part of the World Cup-winning side in 1966 and his all-time appearance and scoring records at Old Trafford have only been eclipsed in recent years.
The late George Best, Charlton and Law -- United's "Holy Trinity" -- scored 665 goals between them for the club and Law relished playing alongside Charlton as much as he admired the man himself.
"What a fantastic player, what a fantastic guy," the former Scotland striker said ahead of Charlton's birthday on Wednesday. "He deserves everything he has been awarded with. He is one of the best players ever.
"It's just that he's done so much for his country, done so much for United. He's probably one of the best known around the world.
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"Don't forget, the television wasn't about in those days like it is today so the fact that he is known all around the world just shows how great a player and person he is."
Law especially admires how Charlton stood strong after surviving the 1958 Munich disaster, in which eight of his United team-mates perished.
"The Munich disaster rebounded right around the world and, you know, you just think 'dear, dear, it's just so close -- I must go and see these guys'," said Law, who was then playing for Huddersfield and went to United's first match after the tragedy.
"When Bobby had the ball I knew where it was going," Law said.
"He had such a strong shot, really, that when he was outside the penalty area lining up for a crack at the goal -- I knew that the keeper might save it, but there was a fair chance he might drop it because it was (hit) so hard.
"Every day Bobby was there, I was lining up to sort of pick up the scraps.
"We had a good relationship. For what he has achieved, he has never changed at all. He's one of the nicest guys you could wish to meet.
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