Pippa Middleton Is Reportedly Pregnant with Her First Child — at the Same Time as Sister Kate!

Double the baby joy!

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A rep for the mom-to-be declined to comment to PEOPLE.

The news came just days before big sister Kate Middleton was admitted to St. Mary’s Hospital in London in the early stages of labor with her third child on Monday morning.

Middleton, 34, and Matthews, 41, tied the knot last year on May 20 at St. Mark’s Church in Englefield. The newlyweds then set off for a whirlwind honeymoon in French Polynesia and Australia.

Image zoom Kirsty Wigglesworth/AP

Just as Middleton famously held her sister’s train during her royal wedding to Prince William, her big sister returned the favor on her special day. And now they’re sharing in the next big milestone: pregnancy.

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Image zoom Samir Hussein/WireImage; Chris Jackson/Getty

Already mom to two children — 4-year-old Prince George and 2-year-old Princess Charlotte — Kate has plenty of sage advice (and designer maternity clothes!) to pass on to her younger sister.

Image zoom Samir Hussein/WireImage

A source previously told PEOPLE that Middleton and Matthews are looking forward to settling down and “having children and leading a quiet life.”

RELATED VIDEO: Kate Middleton Maternity Style Trend Recap: Non-Maternity Pieces, Jewel Tones, and Recycled Outfits!

Pippa’s pregnancy also comes after her father-in-law David Matthews was reportedly arrested in March following accusations he allegedly raped a minor in the late 1990s, according to the Agence France-Presse (AFP) and The Telegraph.