Meghan Markle may start calling Queen Elizabeth this nickname pretty soon

If photos of Queen Elizabeth giggling with Meghan Markle during their first solo appearance together indicates anything, it's that these two royals are *close.* We mean, the queen did give Meghan a little sparkle -- a pair of pearl earrings -- to commemorate the occasion.

While we don't think the queen plays favorites, we're pretty sure Meghan would be on the top of her list if she did.

But how will Meghan know if she and the queen are actually BFFs? According to one expert, it's when the Duchess of Sussex can safely call the queen by her nickname used by her family members closest to her.

According to Majesty editor Ingrid Seward, Meghan can call the queen "Mama" -- but only after a period of time in which she "gets to know her as Diana did."

Before Meghan and the queen get to that level of closeness, Prince Harry's wife shall refer to the queen as "Your Majesty" (with a curtsy of course). After she's passed that level, she can call the queen "Ma'am," followed by "Mama."

And given all the fun the two had this week, if Meghan isn't calling the queen "Mama" right now, we're sure she'll start using that moniker soon.

For more on Meghan, watch the video above.