Meghan Markle's onscreen husband has advised her to "love deeply" ahead of her wedding to Prince Harry

He wrote: "Going to bed now and thinking a lot about the strange surreal and wonderful day my friend Meghan is going to have tomorrow. Meghan - wherever you are - we are so grateful to be here to watch you both take this monumental step together. Love deeply and live well. #RoyalWedding (sic)."

After Meghan, who played Rachel Zane on the show, announced her engagement to Prince Harry, Patrick shared a link to the happy news on Twitter and joked: "She said she was just going on to get some milk."

He kept the gag going on the morning of the wedding, posting an Instagram image of a newspaper showing Meghan and her mother Doria Ragland the day before the nuptials.

He quipped: "I’m beginning to think she might not actually be out getting milk. #royalwedding (sic)."

Meghan, 36, has invited a number of her 'Suits' castmates to the wedding and they have shared their excitement at going to the royal wedding.

Sarah Rafferty - who played Donna Roberta Paulsen in the legal drama - said: "They're a great match."

And asked if they expected to be on the guest list, Gina Torres (Jessica Pearson) said: "I was. I think you know, you hope, and I hope nothing but the best - as we all do - for her, this is an incredible step in her life, so to bear witness to that is extraordinary."

Rick Hoffman (Louis Litt) claims he was the first person the former actress told about their romance and he couldn't believe she was going to join the royal family.

Asked about his reaction, he said: "I was like, 'You've got to be kidding me.' It was like both of us in the trailer, like, 'You're dating a prince.' "

The 47-year-old star said he was sure to advise Meghan not to rush into things and not to get "hurt".

He added: "I was like, 'Take it slow, be careful, don't let him hurt you.' "

Gina added that whilst the couple had to keep their relationship under wraps for some time, because "there was reason to keep [the romance] close to the vest", she could tell how "excited" Meghan was.

Sarah added that the whole 'Suits' cast were like sisters on the show and said the fact they are going to the wedding makes it even more a "family affair".

She said: "We called ourselves the sister wives ... We were with each other for longer than we went to college or high school with our friends.

"So we became family. We're still family, so this is a wonderful family affair."