Sam will be a huge loss,” a palace insider told The Times.
“Going forward, Meghan might need someone cut from a slightly different cloth to traditional courtiers, who is not a career civil servant or royal insider."
A royal source added: “Samantha will assist the couple with finding her replacement in the new year.”
The news comes after Meghan's PA Melissa Toubati quit her job, with sources claiming last week that she found the job “too much” and was left in tears.
A source told the Mirror: “Her job was highly pressurised and in the end, it became too much."
"She put up with quite a lot. Meghan put a lot of demands on her and it ended up with her in tears.
“She is hugely talented and played a pivotal role in the success of the royal wedding. She’ll be missed by everyone in the household.
"Melissa is a total professional and fantastic at her job, but things came to a head and it was easier for them both to go their separate ways.”