That moment everyone's been waiting for is almost here!

With Prince Harry and Meghan Markle's first child expected "any day" now, the Duchess of Sussex's mother, Doria Ragland, has arrived in London, two sources tell ET.

The couple recently moved to Frogmore Cottage, a scenic home near Windsor Castle, where they intend to raise their child. While moving amid a pregnancy -- particularly the final days -- is no doubt a serious undertaking, a source previously told ET that Meghan is "enjoying her pregnancy and anticipating the days ahead." 

"It is such a happy and exciting time for Meghan," the insider added. "She looks absolutely radiant and is taking each day at a time. [She is] looking forward to becoming a mother."

Though the birth could happen anytime now, royal fans won't know exactly when Baby Sussex makes his or her arrival. Meghan and Harry recently announced that -- unlike Prince William and Kate Middleton -- they will not pose for photos with the newborn outside of the hospital immediately following the birth. Instead, they'll share photos taken on the grounds of Windsor Castle at a later date.

"Meghan Markle does not want the pressure of having to pose on the steps for cameras so soon after childbirth," a source recently told ET, adding that, while the couple is "extremely excited" for the birth of their first child, they intend to "enjoy the magic of childhood without any undue expectations."

Markle's mother's arrival coincides with another important occasion -- Queen Elizabeth II's 93rd birthday on Sunday -- which the couple celebrated with a very special Instagram post for the beloved matriarch. 

"Happy Birthday Your Majesty, Ma'am, Granny," the pair captioned a series of photos on Instagram documenting the Queen's life, including her time with both of them. "Wishing you the most wonderful day! ?Harry & Meghan."

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