Meghan Markle finally fell out with future sister-in-law Kate Middleton at the rehearsal for her royal wedding — because of a squabble they had over wearing tights, a friend has claimed.

Markle and her royal beau Prince Harry were already upset with his brother, Prince William, and his wife for failing to welcome the “Suits” actress into the royal household, a close friend told Tatler magazine.

But the final straw came with “an incident at the wedding rehearsal” for Harry and Meghan’s eagerly awaited 2018 royal wedding, the friend says of the falling out many believe ultimately led to Megxit.

“It was a hot day and apparently there was a row over whether the bridesmaids should wear tights or not,” a friend of the Duke and Duchess of Cambridge told the mag for its cover story.

“Kate, following protocol, felt that they should. Meghan didn’t want them to,” the friend insisted.

Markle won, it seems — with photos from her big day at Windsor Castle showing bare-legged bridesmaids.

The Sun previously reported Meghan left Kate in tears with her demands for what her daughter, Princess Charlotte, needed to wear to the wedding.

By that stage, Harry was already “hurt and incensed” at how his future wife was being treated, especially by his sister-in-law, friends said.

“I don’t think that she ever pulled Meghan under her wing and said, ‘I’ll show you the ropes,’” one friend told the high-society mag. “William rightly cautioned Harry to slow the relationship down. That’s why they all fell out.”

Kensington Palace released a rare statement over the article, attacking it for “a swathe of inaccuracies and false misrepresentations” with sources telling People the main anger was at the suggestion Kate feels overwhelmed and resentful at her heavier post-Megxit workload.

Tatler released its own statement, saying it “stands behind the reporting,” which it had asked Kensington Palace to try to “work together.”