Prince William and Princess Kate snub Prince Charles' birthday party - and you'll never guess why

 Prince Charles is gearing up to celebrate his 70th birthday today, but his eldest son and daughter-in-law won't be with him during his milestone birthday!

Kate and Wills have embarrassingly double-booked themselves on the future king's big day and they will be no-shows at a special party held by the Queen for her son.

Kensington Palace have announced that the two will be in the north of England that day to open McLaren Authomtive's new Composites Technology Centre. And then they are visiting a homeless hostel. 

At the same time the Queen will be hosting a fancy bash at the state rooms in Buckingham Palace for family and close friends. 

Awkward. 

It's been revealed that William and Charles have had a difficult relationship following the death of Princess Diana. Prince William appeared in a TV documentary to celebrate Prince Charles' birthday and admitted he wished his dad would find time to visit his grandchildren

In the show, Prince Williama dmits Prince George, 5, Princess Charlotte, 3, and Prince Louis, six months rarely see Grandad. 

William says, "I would like him to have more time with the children. Having more time with him at home would be lovely, and being able to, you know, play around with the grandchildren. When he's there, he's brilliant, but we need him there as much as possible."

This is the THIRD time the two haven't attended birthday festivities for Charles. Prince William and Kate didn't attend the garden party that was held in Charles's honour back in May, because Kate was still on maternity leave.

Last month, his wife, Camilla, organised a huge gala for her husband, and they were no-shows to that as well!

What's going on?