Prince William and Princess Kate were asked to share their most-used emojis — and one of them gave a surprisingly NSFW answer.

“Is this a clean thing or is this a family one?” William, 41, joked during a Tuesday, October 10, appearance on the BBC Radio 1 show Going Home. “I’ve been told not to say the aubergine, so I’ve got to pick something else.”

Aubergine, for those readers unfamiliar with British English, is just a fancy way of saying eggplant.

“It would have been the aubergine, but I’m saying now — because I’ve got to be all grown up — it’s the one where the eyes go up and down and the mouth’s out,” William continued. “What’s that one? The slightly crazy one.”

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Going Home’s hosts, Jordan North and Vick Hope, were endlessly amused by the prince’s answer. “He said the aubergine emoji, this is brilliant!” North, 33, remarked, while Hope, 34, added, “He knows. He’s got a dirty mind.”

Kate, meanwhile, had no difficulty coming up with a family-friendly answer. “Mine’s probably going to be the heart with then the crying emoji,” the Princess of Wales, 41, said. “The hysterical laughing when things have gone wrong.”

While William and Kate were happy to joke around about their texting habits, the couple’s visit was timed to a more serious occasion: World Mental Health Day. During a forum the duo cohosted in Birmingham, England, William shared some of his own tips for mental well-being — and revealed that laughter is often the best medicine for him.

“Humor for me is a big deal — I love to laugh,” the Prince of Wales explained. “You’ve got to look at the lighter things in life sometimes to feel good.”

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He went on to say that he also likes to take walks to get some “fresh air” and make sure that he spends time away from screens. “Time with my friends, time with my family,” he added. “Things like that really matter to me.”

Kate, for her part, said that she’s inspired to see so many young people speaking up about mental health after years of stigma surrounding the topic.

“Today, more people feel empowered to talk about their mental health than ever before. This is a major step forward,” she said during the forum. “William and I continue to be inspired to see young people, like you all here today, leading this charge — being particularly brave in having some of those conversations yourselves. As a generation, you value and talk more about your mental health than any before you — something we truly admire and applaud.”