A third joked: "I often feel annoyed my hair is thinning, but then I see Prince William's transformation, and I feel a bit better about myself."
On the other hand, someone else has "respect" for the prince for accepting himself and added: "I respect Prince William. Surely he has the facilities to get hair transplants, but he's owned that he's balding. Gotta give props there."
In the past, Prince William has made jokes about his lack of hair.
In 2019, the royal visited a barbershop in London and poked fun at his hair routine.
"I don't need a haircut anymore. I just take a razor to it!" he teasingly said.
The Prince and Princess of Wales are officially on the third day of their Boston trip, where they will be presenting the royals' Earthshot Prize Awards ceremony today (2 December).
The achievement is given out annually to five people based on their contributions to environmentalism.
Each recipient will also be awarded $1.2m.
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