Kensington Palace says Meghan Markle is suffering a "deeply personal moment" following reports her father will not attend her wedding to Prince Harry on Saturday.
Celebrity news website TMZ said Thomas Markle, who recently posed for paparazzi photos, has pulled out of accompanying his daughter down the aisle at Windsor Castle because he does not want to embarrass her.
Markle is also reported to have suffered a heart attack in recent days.
"This is a deeply personal moment for Ms Markle in the days before her wedding," read a notice from the official residence of the couple. "She and Prince Harry ask again for understanding and respect to be extended to Mr Markle in this difficult situation."
The US actress' father had previously defied the palace's pleas for secrecy by agreeing to pose for a paparazzi photoshoot.
The images, showing him being measured for a suit and admiring a photo of the couple on his computer, sold for US$100,000 (HK$1.06 million).