Prince Harry and Meghan Markle
Prince Harry and Meghan Markle's wedding invitation break another royal tradition. Pictured: Prince Harry and Markle arrive at the Eikon Centre in Lisburn, on March 23, 2018, to attend an event to mark the second year of youth-led peace-building initiative Amazing the Space. Getty Images/Mark Marlow

Meghan Markle and Prince Harry's wedding guests will be able to witness their union, but their invitation comes with one condition.

It is given that Markle and Prince Harry's nuptials will not be as grand as Prince William and Kate Middleton's lavish royal wedding in 2011. The engaged couple opted for a smaller venue, which can only accommodate 800 family, friends and peers. As a result, some of the guests will have to leave their partners at home when they attend the event.

"Unlike most other weddings, Harry and Meghan are inviting only one half of couples. Seen an invite for a husband but not his wife. Sounds a bit tight, but I'm sure they'd claim space in limited in St George's Chapel... #RoyalWedding," Chris Ship, ITV News royal editor, wrote on Twitter.

In another post, Ship gave an update saying that he saw another invitation, but this time, both the husband and wife were invited. However, the editor couldn't get over the first card he saw that only invited the man. "But isn't normal practice always to invite married guests as 'couples'?" he asked.

One of Ship's followers provided an answer to his query. "Guest lists are just the same like one of us, my brother got married last year and couldn't invite all the wives/partners of his mates, there just isn't enough room for everyone you have to choose," Lindsey Churm wrote.

Ship got her point and agreed. "You're right. It's a space thing," the editor replied.

In related news, there is still no update as to who is designing the "Suits" star's wedding dress. However, Katie Nicholl gave a few details as to what fans can expect for Markle's bridal gown.

"I'm told that she wants something with lace, that she wants something with sleeves," Nicholl told Entertainment Tonight. "Of course she's dressing for the rather inclement British weather, but more than that she's dressing for a very, very important occasion. So I think you will be probably pleasantly surprised for Meghan the 'rule breaker' when it comes to this dress. I think it's gonna tick all the right boxes: traditional, elegant, sophisticated, memorable, and fitting."

However, the royal biographer believes that Markle will not spend so much for it and upstage Kate Middleton, who is the future queen.

Meanwhile, when Middleton's Alexander McQueen wedding dress was also in the works, the project was considered top-secret. In fact, no one knew who was working on it until her big day.

Markle's gown is expected to be treated the same, so fans may have to wait until the royal wedding to learn the details of her dress.