The group also include the three children of Jessica Mulroney - Meghan's close friend who has previously worked as her stylist and reportedly helped Meghan in the planning and lead-up to the wedding - though there is no official maid of honour.
Doctors "will go in and clear blockage, fix damage and put a stent where it is needed", the 73-year-old was quoted as telling TMZ, which said Markle realised it was all but impossible he would be able to walk his daughter down the aisle.
Markle Sr. told TMZ earlier this week that he thought it was best to avoid his daughter's wedding in the wake of a British newspaper's report that he staged paparazzi photos earlier this year near his home in Mexico.
Prince Harry's press office said Wednesday there is no additional comment beyond a statement made two days ago calling for respect for Markle's father, Thomas.
Details about the wedding have been closely controlled by Kensington Palace but reports of Mr Markle's intentions have thrown their intricate plans into flux.
Thomas's decision left arrangements for the Royal wedding in doubt, and Meghan without her father on the biggest day of her life. The royal wedding of Meghan and Prince Harry will take place on May 19.
So if her dad is out of action, who could walk the future Royal down the aisle on Saturday?
An illustration shows a box of Crown Jewels condoms limited edition unofficial Royal Wedding souvenir box. Daniel Sorabji AFP
In the months and weeks leading up to the wedding, photogs had snapped photos of Thomas Markle reading a book about Great Britain, working out and getting fitted for a suit (presumably for the wedding).
If he does not attend, Meghan's mother may walk her down the aisle instead.
According to the outlet, the former actress told her father she loved him and "was concerned about his health".
"I don't think the Queen is thinking about what I'm doing", he was quoted as saying.
Whether he attends the wedding will be based on "whether or not it's safe" for him to go, said Grant.
So who is Thomas Markle?
Just hours later, though, he checked himself back into the hospital after suffering chest pains, which is when he found out he'll need to have the surgery, therefore making him unable to take the long trip across the pond.
Ragland, a social worker and yoga instructor, will meet Harry's royal relatives and be introduced to various friends of Harry and Meghan's over the next few days.
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