When Meghan Markle weds Prince Harry in May, she’ll get titles, castles, staff – and, according to reports, a purpose-built new best friend in the Duchess of Cambridge.

The women are already neighbours at Kensington Palace, where Kate and husband Prince William live in the 20-room, four-storey Apartment 1A and Meghan lives with Harry in the more humble two-bedroom Nottingham Cottage.

While initially there was buzz that Kate – a long-time Harry confidante who watches Games of Thrones with him – could resent having a rival for the spotlight landing at the palace, the established royal is already fast friends with Meghan, say latest reports.

Hopefully the claims are true, because the ladies are stuck with each other. Not only will they become sisters-in-law, they’ll also be business partners when Meghan joins Harry, William and Kate as patron of The Royal Foundation, sharing their workload and social media handles.

“Not since the 1980s heyday of Princess Di and Fergie have a pair of royal partners so captured the imagination,” said People magazine’s senior royal editor Michelle Tauber.

Meghan Markle (in Stella McCartney and skinny jeans) on the job in Wales on January 18. Photo: Getty

More than being a friend, Kate is reportedly acting as mentor to Meghan, given she’s one of the few people in the world who can help her navigate the weirdness of her royal role.

The two women met in January 2017 when Meghan dropped off a birthday present for Kate – a dream diary – at the palace.

They caught up behind closed doors after that whenever Meghan was in London, and after her engagement was announced the former Suits star said Kate had been “wonderful” in her support, which is “really, really special”.

“I’m sure Kate will do all she can to help Meghan,” a source in the Middleton family’s hometown of Bucklebury told People.

A palace insider told E! it’s a “big priority” for the royal family and staff to ease Meghan into her new life. Kate is the pinch hitter: “Catherine is very aware that Meghan will need a friend alongside her while she gets used to the way things are done around here.”

The Duchess of Cambridge in Catherine Walker with Chanel bag in Stockholm on January 31. Photo: Getty

Still, while Kate knows the royal ropes, Meghan is no novice at public life. Her past career in Hollywood and as a UN Women advocate means she’s comfortable in front of a camera or microphone.

“Meghan is far more worldly and sophisticated than Kate was when she arrived on the scene,” said Majesty magazine editor 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.”

In terms of reversed roles, Meghan’s edgier fashion style has already perhaps impacted on Kate’s usually-conservative choices.

On the first two days of her Scandinavian tour with William, she’s showcased a smorgasbord of high end rather than high street looks – chartreuse Erdem, Alexander McQueen– and ditched her dated signature LK Bennett nude pumps for strappy Gianvito Rossi sandals.