Samantha Markle admits she never expected to get an invite to the royal wedding as she was omitted from the guest list for Meghan's first marriage. Picture: YouTube/Screengrab

Meghan Markle's half-sister Samantha Markle has claimed her sibling has not provided her family with any support since she got engaged to British royal Prince Harry.

The former 'Suits' star will tie the knot with the prince on Saturday at St George's Chapel at Windsor Castle and there are several family members who she has left off of her guest list, including Samantha, her nephew Tyler Dooley and his mother Tracy - who was previously married to Meghan's half-brother Thomas Markle Jr.

In an interview with UK TV show 'Loose Women', which aired on Monday, Samantha also revealed that her and Meghan's dad Thomas had struggled to deal with the sudden scrutiny into his life.

Speaking about her father, she said: "Let me clarify, he's 73, which makes him a bit more fragile. He's a quiet man. I feel he's been unfairly preyed on. He's really been admirable about laying low and not speaking out, with all due respect."

Samantha - who lives in Florida - admits she never expected to get an invite to the royal wedding as she was omitted from the guest list for Meghan's first marriage to Trevor Engelson, which took place in Jamaica.

Although she won't be at the ceremony rubbing shoulders with Harry's grandmother Queen Elizabeth II, his dad Prince Charles or brother Prince William, Samantha will be watching on TV like the rest of the world.

She said: "I have to say, I'm not taking it personally. It's not just me. None of the family have received invites. Although we don't understand we can only wish them well. I'm not taking it personally, nor am I holding it against her."

"Also for some of us the travel is not very easy. I am in a wheelchair. I had to evaluate even if I had been invited, it would have been a bit difficult. But for everyone else in the family, I can only think that schedules might have been in the way. Nonetheless we wish her well, it is what it is."

Specifically asked whether Meghan has offered any support to the family, she said: "No and I know that she's been overwhelmed, so you know, we don't really understand and I guess because we don't understand, it shouldn't be held against her. I think clearly there's a lot of room for open communication."