Everyone's on pins and needles awaiting the birth of the royal baby -- none more so than Prince William and Kate Middleton's immediate families. As previously reported, the Duke and Duchess of Cambridge, both 31, arrived around 6 a.m. Monday, July 22 at St. Mary's Hospital in London, checking into the Lindo Wing (where both William and brother Harry were born).

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"Things are progressing normally," a palace aide told Us. Great-grandmother-to-be Queen Elizabeth is being kept apprised of the situation and is currently at Windsor Palace with husband Prince Phillip, and is expected to travel back to Buckingham Palace later today. First-time grandfather-to-be Prince Charles is currently 200 miles away for a previously-arranged engagement in York. When asked of the latest baby news, Charles, 64, told reporters he knows "Absolutely Nothing. We're waiting."

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When one reporter asked if the future King or Queen could arrive in six hours, he demurred, "might be." (Although not present for Monday's engagement, Charles' wife Camilla, Duchess of Cornwall, is also in York for the two-day engagement.)

Middleton's own parents Carole and Michael Middleton -- Kate and William stayed at their Bucklebury home last week -- were reportedly en route from Bucklebury to the hospital by midday Monday.

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First-time uncle-to-be Prince Harry, alas, is currently station at Royal Air Force base Wattisham with his Apache squadron.

Kate and William's private secretaries, Miguel Head and Rebecca Deacon, are presently inside the hospital.

This article originally appeared on Usmagazine.com: Kate Middleton in Labor: How Royals, Middletons Are Waiting Out Royal Baby's Birth