Kate, who was once mentored by Queen Elizabeth, is now a support for Meghan

Kate Middleton and Meghan Markle are poised to become sisters-in-law in May — but they have already begun leaning on each other.

“I’m sure Kate will do all she can to help Meghan,” a source in Kate’s hometown of Bucklebury tells PEOPLE, while noting that in the early years of her romance with Prince William, Kate herself was mentored by Queen Elizabeth. “She had audiences with Queen Elizabeth quite often and was taught to behave like a future Queen.”

Unlike Kate, whose husband is second in the immediate line of succession, Meghan has ample breathing room between herself and the throne: Prince Harry will downshift to sixth in line with the arrival of William and Kate’s third baby in April.

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Meghan, who will be learning on the job, “is funny and serious and extremely hard-working,” says a source close to the former Suits star. “I can imagine Kate will find a great friend in her.”

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Prince William, Princess Kate, Meghan Markle and Prince Harry at Sandringham on Christmas Day 2017.
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The two women, both 36, have quickly bonded, helped by their close proximity as neighbors at Kensington Palace. Of course, their paths to the palace were very different: Kate, who enjoyed a bucolic childhood in the English countryside, was a 19-year-old student at St. Andrews University in Scotland when she met fellow art history major Prince William. Across the ocean, Meghan — whose parents, onetime TV sound engineer Thomas Markle and yoga instructor Doria Ragland — was cultivating her interests in acting and activism at Northwestern University in Illinois.


For much more on Meghan and Kate’s blossoming friendship, pick up this week’s issue of PEOPLE, on newsstands Friday

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By the time Meghan met Harry in July 2016, she had an established career as an actress and had been through 2013 divorce from producer Trevor Engelson.

“Meghan is far more worldly and sophisticated than Kate was when she arrived on the scene,” says royal biographer Ingrid Seward. “She was in one of the toughest businesses in the world and did well in it. She’s a divorcée and had some of the ups and downs in life. Kate has lived a rather charmed existence.”