Prince Harry and Meghan Markle's wedding: Which celebrities could be invited?

Following the announcement that Prince Harry and Meghan Markle are engaged, speculation around their upcoming nuptials has kicked into high gear.

On Tuesday morning, one day after the engagement reveal, it was announced that their wedding would take place in May of 2018 on the grounds of one of Queen Elizabeth's castles. St. George's Chapel is located at Windsor Castle, where the Queen lives for part of the year. Her Majesty has given permission for the wedding to take place there.

SEE ALSO: Prince Harry says Meghan Markle and Princess Diana 'would have probably been best friends'

But one of the many remaining mysteries about the next royal weddings is who will snag invites.

See photos from Meghan Markle and Prince Harry's engagement photo call:

Being an actress on the USA Network's long-running hit drama series, "Suits," Markle is surely expected to invite some of her co-stars from the show. She's particularly close to Patrick J. Adams, who plays her love interest on the show, so he will almost certainly be invited -- but will he bring wife Troian Bellisario from "Pretty Little Liars" as his date?

Other possible celebrity invitees include Markle's close pals Priyanka Chopra and Serena Williams, who the actress once referred to as her "confidant." The two stars have been friends for years, though Markle notably didn't attend the tennis legend's wedding earlier this month.

From Harry's side, there's speculation that David and Victoria Beckham are likely to receive invitations to the wedding, too. Former US President Barack Obama is also a friend of Harry's, and the two seemed to grow close after their collaboration on the Invictus Games.

RELATED: See photos from Serena Williams' star-studded wedding:

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