Giggs has joined United manager David Moyes' backroom team.
"It's marvellous to see Ryan Giggs on David's coaching staff," Sir Bobby told manutd.com. "He's a marvellous player, he loves the game of football and he has unbelievable talent.
"His pace, his control and his speed of thought continue to stagger me. He's been a great, great servant here as a player and it's terrific to see him working for the club as a coach.
"I just can't believe he's nearly 40. In my playing days everyone just assumed you were finished when you reached 30, but there he is, still going strong!
"As well as being a great player, Ryan is a terrific talker too, and that part of his game will be important now that he's part of the coaching staff. It's great he's still linked to the club.
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