Patrick J. Adams has revealed new details about the audition that landed Meghan Markle her breakout role in “Suits.”

According to Adams, it was all about easy chemistry.

The “Suits” star, 43, spoke about Markle’s audition on the second episode of his new SiriusXM show, “Sidebar: A Suits Watch Podcast,” which he hosts with Sarah Rafferty, who played Donna Roberta Paulsen on the USA Network series.

Adams, it turns out, worked with Markle, 43, on a “terrible, terrible pilot” before their time together on “Suits.”

“There was a setting up of a romantic relationship in the pilot of that particular pilot too,” the actor said. “And then we never saw each other again. The pilot failed. It was terrible and went away. And so we had never seen each other nor spoken to each other again.”

Years later, Adams booked the lead role of Mike Ross on “Suits.” As he was the first to be cast, the show’s producers were still searching for the actress who would play Rachel Zane, a paralegal and Ross’ love interest.

Ross acted as a scene partner for the actresses who made the final round of auditions — colloquially called a “chemistry read.” As the name indicates, this final test determines whether sparks fly between the actor who already has the job and the auditioning hopefuls.

Adams recalled being surprised when he saw Markle at the chemistry reads.

“She was right there and she said, ‘Hi.’ And I went, ‘Oh my God! So good to see you!’”

According to Adams, the pair’s previous work together helped smooth the actress’ path to success.

“And so I think just knowing each other and getting to calm down and not have those nerves of just getting to know one another really helped that chemistry read,” Adams explained. “And it was just clear that we had an easygoing thing when we went into that room.”

In Adams’ view, Markle was head and shoulders above the competition.

“[I]t was pretty clear, if I remember correctly, that she was going to get the part from the minute we did the chemistry read,” he recalled. “It was just so much easier than it was with anybody else.”

Patrick J. Adams and Meghan Markle on a 2014 episode of “Suits”

When Meghan Markle met Prince Harry in 2016, the now Duchess of Sussex had a major role playing paralegal Rachel Zane in the hit TV show “Suits.”

The scene Markle had to audition with was “a bear of an audition scene,” Rafferty said as she and Adams rewatched the “Suits” pilot.

“[A] big one. And she crushed it,” Adams added. “She crushed it, and she crushes it in the show.”

Markle getting the job on “Suits” was a pivotal moment in her career. But, according to royal biographer Andrew Morton, “Meghan didn’t feel great about her audition.”

In his book “Meghan and the Unmasking of the Monarchy” (an updated version of his tome “Meghan: A Hollywood Princess”), Morton writes that Markle called her agent in the car on the way back from the audition, bereft.

“She told him that she could not get her head around the lines. It was a mouthful, the worst audition of her life,” Morton claims.

“’I don’t think I did a good job in that room, and I need to get back in there,’ she wailed. ‘I really want this part.’”

But Markle didn’t need to worry. The show’s creator, Aaron Korsh, told Vanity Fair in 2017 that she aced the audition.

“We all looked at each other [after Markle’s screen test] like, Wow, this is the one!” he said. “I think it’s because Meghan has the ability to be smart and sharp but without losing her sweetness.”

Patrick J. Adams and Meghan Markle on “Suits.”

Markle also made a last-minute move before her audition that played a pivotal role in getting the gig: she went to H&M for a new dress.

“Meghan had dressed sexy-professional-casual to screen-test for the role,” Morton writes. “Somewhat belatedly, she realized that the plum-coloured spaghetti-strap top, black jeans and high heels she was wearing were more single lady lawyer on the prowl than attractive paralegal with an encyclopedic knowledge of the law.”

“So, just before her audition, Meghan had run into an H&M store, picked out a simple black dress for $35 and raced back to the studio.”

According to the royal author, “She hadn’t even had time to try it on for size,” but the producers asked her to wear the dress rather than the jeans and top.

As Morton put it, “It was the best $ 35 she had ever spent.”

New episodes of SiriusXM’s “Sidebar: A Suits Watch Podcast” are available every Tuesday on the SiriusXM app and wherever podcasts are available.