Prince William left red-faced during a show

Prince William, during a show with his wife Kate Middleton, prompted one of the hosts to accuse him of having a 'dirty mind'.

It happened when the future king revealed his most-used emoji during a radio show appearance, sharing interesting details about the emoji, which is often used during more explicit conversations.

BBC Radio 1's Going Home show Host Vick Hope asked William which of the characters he uses most frequently, the Prince responded as saying: 'Is this a clean thing? Is it a family one?'

Meanwhile, Princess Kate quipped: 'It depends what group, if it's the family WhatsApp group.'

However, William's favorite emoji may not be what you'd expect as the future king revealed: 'I've been told not to pick the aubergine, so I've got to pick something else.'

William went on revealing the truth, saying: 'It would have been the aubergine, but I'm saying now because I've got to be a little grown up that it's the one with the eyes [that] go up and down, and the mouth.'

The hosts of the show were surprise and delighted at William's response, with Jordan saying: 'He said the aubergine emoji, this is brilliant.'

Co-host Vick left the heir to the throne red-faced with his joke as he reportedly said: 'He knows. He’s got a dirty mind.'

Meanwhile, Princess Kate for her part made a less risqué choice and admitted that her favourite emoji was "the heart with then the crying emoji." 

The future queen explained: "The sort of like ‘hysterical laughing’ when things have gone wrong."

It's to mention here that royal emoji use has been put under the microscope for years, with headlines around the world analysing Prince Harry’s unconventional preference for the ghost emoji.