The actor, who is a friend of the British royal and her husband Prince Harry and attended their royal wedding with his wife Amal last May (2018), gave the warning after U.K. tabloid the Mail on Sunday published a letter Meghan reportedly wrote to her estranged father, Thomas Markle.
According to the Press Association, during a panel discussion promoting his new Hulu show "Catch-22" in Pasadena, California on Monday, February 11, George criticised those hounding the pregnant Duchess.
"I do want to say, I just saw this piece," he said. "They're just chasing Meghan Markle everywhere, she's been pursued and vilified. She's a woman who is seven months pregnant and she is being pursued and vilified and chased in the same way that Diana was, and it's history repeating itself. And we've seen how that ends. I can't tell you how frustrating it is to see that."
Harry's mother Diana died in 1997 in a car crash in Paris caused when her driver was speeding to avoid photographers. She had been under intense media scrutiny for several years after the breakdown of her marriage to Prince Charles.
The "Gravity" star went on to directly reference the alleged handwritten letter, in which Meghan reportedly accused her dad Thomas of having "broken my heart into a million pieces" by telling falsehoods to the media.
"You're taking a letter from a daughter to a father and broadcasting it everywhere," he added. "She's getting a raw deal there, it's irresponsible. I'm sort of surprised by that."
Shortly before his daughter was due to wed Harry, Thomas staged paparazzi photos of himself preparing for the wedding. He then cancelled his trip to the U.K. for the nuptials and has subsequently made several public appeals calling for Meghan to repair their relationship - with the latest an interview accompanying the letter's publication in the British tabloid.