Speculation of tensions between the Cambridges and the Sussexes began to surface at the end of 2018, shortly after it was announced that Harry and Meghan would be moving to Frogmore Cottage in Windsor.
There were reports of a feud between the royal sisters-in-law, with sources saying Kate "was left in tears following a bridesmaids dress fitting for Princess Charlotte," during preparations for Harry and Meghan's wedding.
There were other rumours about a fall-out between the brothers, with William reportedly airing concerns about Harry's relationship with Meghan and how quickly it was moving.One royal author thinks that the rumours of a rift are "undoubtedly true."
Speaking on Yahoo UK's 'The Royal Box,' Anna Pasternak says: "William is very responsible and knows what his role is and Kate has come alongside that and executed that extremely well.
"I think it's quite difficult to have had Meghan, who seems to want to modernise and set her own agenda.
"You can't have it all. You cannot have your freedom and this privilege, so it is a Faustian pact. It's not a fairy tale and [Megahn needs to] recognise that and live with the consequences."
Kensington Palace have not commented publicly on any of the alleged feud rumours.
Earlier this month, it was announced that the Sussexes will have their own royal household, based at Buckingham Palace, formally splitting from their joint office with the Cambridges.
- This article first appeared on Yahoo
Watch the full episode 18 of Yahoo UK's show 'The Royal Box,' here.