Markle was seen in London on Friday before the ceremony.
The fact that she will attend the wedding — even if it’s the post-church nighttime bash — is yet another sign that the Suits actress and the prince, 32, are getting more and more serious.
Myka Meier, founder and director of Beaumont Etiquette, tells PEOPLE that while there is no formal “no ring, no bring” rule, it isn’t surprising that Markle didn’t get an invite to the church wedding as Middleton would likely want to keep her actual wedding small.
“I would not be surprised if Prince Harry was not given a plus one, as the wedding guest list would have most likely been made in fall of last year when Prince Harry’s relationship with Meghan was not as public,” Meier said. “I typically recommend if someone is married, engaged, considers themselves to have a serious significant other, or is traveling in for the wedding, they should receive a plus one.”
The fact that Pippa’s brother, James Middleton, brought his longtime girlfriend, Donna Air, means she didn’t opt for the “no ring, no bring” rule. Princess Eugenie also attended with her longtime boyfriend, Jack Brooksbank.
If Markle had attended the ceremony, it would have been a major moment, as it would be the first time the two royal couples — Will and Kate and Markle and Harry, would have been pictured together in public.
The duo was recently snapped sharing a sweet kiss and embrace following Harry’s charity polo match earlier this month — marking the first public event they have officially attended as a pair.
“Despite the distance, the media attention and everything else, there’s a real ease to their relationship,” a source recently told WHO of the pair. “It just works. They are deeply happy.”
This story originally appeared on PEOPLE.com.