The fully clothed prince attended the WellChild Awards Ceremony last week and joked with children at the event. ITV, a British TV network, reported that one of the children, a 6-year-old boy named Alex Logan, said he planned to tell the prince he was "glad he got his clothes on" when he met the royal.
The boy's mother, Debbie Logan, said Prince Harry told him not to go there when they met.
"Harry said to Alex, 'You keep looking up at your mum, looks like you're dying to say something, but you know she will tell you off," Logan told ITV. "I hear you were on ITV earlier, you said something cheeky. Let's not talk about that here."
ABC News' Jean-Nicholas Fievet and Erin McLaughlin contributed to this report.