The Beatles legend insists Stella - who is a renowned fashion designer - was destined for greatness because she had him and his late wife Linda as parents.
He said: "Well, the genes are there. She's a very clever girl."
Paul made the comments after Stella was honoured at the Natural Resources Defense Council's (NRDC) annual Forces For Nature benefit in New York for her environmental work.
The 37-year-old designer is a staunch vegetarian - like her mother, who promoted her meat-free lifestyle with her own range of vegetarian foods - who refuses to use fur or leather for her label.
Paul added: "She's very brave, and she has solid principles that she's stuck with against all odds, so I respect her for that. I'm a very proud dad."
Speaking before the ceremony, NRDC chairman president Frances Beinecke said: "Stella demonstrates that you can be a protector of the environment and a leader of industry at the same time."
The event had a green theme, with actor Alec Baldwin arriving in an environmentally-friendly hybrid Sports Utility Vehicle.
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