Prince Harry and Meghan Markle have figured out their royal wedding guest list, so if you think you have a shot of watching them walk down the aisle in person, you'll want to keep an eye on your mailbox.

The soon-to-be royal couple is ready to sign, seal, and deliver their happy news before walking down the aisle at St. George's Chapel at Windsor Castle on May 19, and while the full guest list has not been publicly confirmed (and likely won't until the big day), we do know a few people who have been asked to make an appearance at the celebration ... including Prince Harry's ex-girlfriend Chelsy Davy.

Prince Harry Meghan Markle
Credit: BEN BIRCHALL/AFP/Getty Images

Davy and Prince Harry dated on and off for around six years before calling it quits around 2011, but there's evidently no bad blood between them. E! News confirmed that Davy has been invited, and a source told the outlet that "She and Harry talk regularly."

While that may seem odd, it's actually not that weird for royals to invite their exes to weddings. According to People, both Prince William and Kate Middleton invited exes to their 2011 wedding, so it's almost as though Harry is following in their footsteps. While Markle's got a high-profile ex in her producer ex-husband Trevor Engelson, USA Today reports that he is not expected to receive an invite.

The rest of the guest list for the ceremony (St. George's Chapel can hold 800 people) is less eyebrow-raising and includes a lot of Prince Harry and Markle's family members. USA Today says Markle's parents Doria Ragland and Thomas Markle will be chosen by Markle to attend, though there's no word yet on her two half-siblings, the outspoken Samantha Grant and Thomas Markle Jr.

Prince William will attend and will be Harry's best man (though as of January, he hadn't asked him yet), and though Kate Middleton will not have a role in the ceremony, she will be attending. They are obvious familial invites, but there are some more surprising ones.

According to E!, Sarah Ferguson, Duchess of York (also known as Fergie) received an invite, despite being left off of Prince William and Kate Middleton's guest list reportedly because of a feud between her and Prince Philip.

"Prince Harry and Princess Eugenie [Sarah's daughter] are very close, and therefore I wouldn’t be surprised to see her welcomed back into the family fold for at least part of the wedding,” People Now royals contributor Imogen Lloyd Webber said earlier this month. “If not the church ceremony, then maybe the wedding reception.”

Since this Ferguson-inclusive guest list hasn't been formally released, nobody has seen Markle and Prince Harry's official wedding invites except those who have been lucky enough to receive them, and that exclusive list includes Mel B. The singer stopped by The Real talk show this week, and she revealed that the Spice Girls have all been formally invited to the royal wedding.

After nodding when co-host Loni Love asked her if she was going, she elaborated. “Well, it was [the] five Spice Girls. Why am I so honest?” she said.

“So they invited all five Spice Girls to the royal wedding?” Love questioned.

"Yes," said Mel B. While she was hesitant to divulge much else—coyly saying "Ah, swear I'm just like ..." when asked if she and the Spice Girls were going to perform at the wedding—she did give a little insight into what the invitations look like.

"It was proper. I’m not saying anymore! I’ve said enough. … I need to go. I’m gonna be fired!"