Meghan Markle says her father will not attend her wedding to Prince Harry on Saturday.
In a statement, she said she had "always cared" for her father and hoped he could be given the space he needed to focus on his health.
In recent days, doubts had been raised over whether Thomas Markle would be at the wedding to walk his daughter down the aisle.
On Wednesday, it was reported that he had to undergo heart surgery.
Markle had been due to meet the prince for the first time this week, as well as the Queen and the Duke of Edinburgh.
The couple can expect a sunny and breezy day, with temperatures reaching up to a balmy 21C in the late afternoon.
Markle, who is understood to be in Mexico, was caught up in controversy after allegedly staging photographs with the paparazzi.
He later told US celebrity news website TMZ he would not attend the wedding amid the controversy; then that he would; and then that he could not, due to a planned heart procedure.
Ms Markle's estranged half-sister, Samantha, said he had faced "unbelievable stress".
His absence leaves a big question mark over who will walk Ms Markle down the aisle.
Her mother, Doria Ragland, who arrived in the UK on Wednesday, would be one option, as would Prince Charles, Harry's father, or she could choose to walk alone.
Ms Markle has 10 bridesmaids and pageboys, all under the age of eight.
She decided against having a maid of honour because she wanted to avoid choosing between her closest friends.