The Kensington Royal Instagram account posted a sweet split picture of Prince Charles with sons William and Harry, accompanied by a snap of William and his own son George, leaving his daughter Princess Charlotte notably absent from the message.
'Lovely picture...however where is Princess Charlotte?' one follower wrote, whilst another agreed: 'Actually they're parents to two children, why wouldn't you post a photo of the parent with both kids?'
'No Charlotte???' a third commented. 'We don't seem to see much interaction between William and Charlotte. More so William and George.'
'It's Father's Day. Not sons day. He is father to a daughter, as well,' another said.
'Its too sad Charlotte doesn't appear there. There is not enough photos of the princess and her father. 😪' one observed, whilst a similar message read: 'Not to have his daughter in this post is soo wrong. When she grows up and see this, how do u think she gonna feel? Wow.'
Others mentioned that the account had not done a comparable post for Mother's Day, although it was pointed out that it may have felt inappropriate to do so given the sad loss of William's mother, Princess Diana, in 1997.
'Social media is not the place to talk about her and Mother's day,' one Instagram user argued.
However, despite the controversy about the choice of image, there were plenty of positive comments left on the post too, with many calling it 'so sweet' and 'adorable', and wishing Charles and William a happy Father's Day.
'Such a loving family it makes me want to run over and grab all and give a hug happy Father's Day,' said one follower.
'The photo of Prince William and Prince George is absolutely adorable!!!' a second exclaimed, whilst a third added: 'Great Photos, have a lovely day'.