With the mother and daughter being so close, it's hardly surprising that Doria has a special role on the day, set to stay with Meghan in Windsor the night before the wedding and then ride in the vehicle to the church with her.
The American TV actress' family has been in the news for their controversial statements about the bride-to-be.
The TMZ website reported on Monday that he had decided not to attend the glittering wedding at the castle, the home of English and British monarchs for nearly 1,000 years. He also said he had suffered a heart attack a week ago.More news: Neymar Admits He's 'Afraid' Ahead of Return from Injury, World Cup
It was that incident, where Mr Markle was caught setting up paid paparazzi photos of him Googling his own daughter, that reportedly prompted his withdrawal from the wedding.
Kensington Palace said when details of the cake were unveiled: "Prince Harry and Ms Markle have asked Ms Ptak to create a lemon elderflower cake to incorporate the bright flavours of spring".
On Tuesday, TMZ reported that Thomas Markle said that on reflection, he did want to come, if doctors release him from a hospital where he was undergoing tests after a heart attack.
Despite telling TMZ that he didn't want to miss "one of the greatest moments in history", Thomas Markle ultimately decided that he will not walk his daughter down the aisle or be present for the nuptials due to his health. "That was not the motive - it was my suggestion", she said.More news: Buffalo Bills announce Thurman Thomas' No. 34 jersey will be retired
The former even wrote an open letter to Prince Harry, urging the royal to not marry Meghan.
But he later said doctors had scheduled surgery on Wednesday morning.
Thomas Markle spent a career in Hollywood, but nothing prepared him for this.
Britain's Prince Harry and his fiancee Meghan Markle attend the Dawn Service at Wellington Arch to commemorate Anzac Day in London, Britain, April 25, 2018.
But Ragland is perhaps most likely to take on the task, given her particularly close relationship with her daughter.More news: NAFTA deal unlikely this week, but negotiations continue, Mexico says
Thomas Markle, if you somehow don't know, is Meghan Markle's father. He feels that anyone who gets associated with his life - this is the price they have to pay. "I searched the world for something that I thought was really sentimental", she said.