Meghan Markle's wedding guests were worried about her close friendship with "Suits" co-star Patrick J. Adams, said a royal biographer.

The Duchess of Sussex's role Rachel Zane was the love interest of Adams' role Mike Ross and their on-screen chemistry worked well.

According to royal author Andrew Morton in the book "Meghan: A Hollywood Princess," co-stars' close bond caused wedding guests at the "Suits" actress and Trevor Engelson's wedding in 2011 to raise their eyebrows.

"The first episode of Suits aired on June 23 to generally favorable review and, more importantly, an enthusiastic audience. Cast, crew and the money men at the network were ecstatic, the producers thrilled that their gamble to cast Meghan opposite Patrick had paid off big time, the show's fans buzzing about the couple's on-screen chemistry," Morton narrated.

Their chemistry was reportedly just as lightning off-screen.

Morton said their off-screen chemistry was equally apparent and was uncomfortable, according to guests at Markle and Engelson's wedding, which was held in Jamaica in 2011.

"The two actors clearly developed a bond of familiarity that is invariably the corollary of working up close and personal for so long and so intensely," Morton said.

The former couple decided to get divorced 2 years later. During that time, rumors circulated that the duchess called their marriage off possibly due to dishonesty and lies.

It is a common phenomenon that actors playing as love interests eventually become a real-life item. Examples are Brad Pitt and Angelina Jolie and Daniel Craig and Rachel Weiss.

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Adams Was Once Attracted to a Co-Star

Adams himself became attracted to an earlier co-star, Troian Bellisario, who he starred with on the play "Equivocation" in 2009. They dated for a year and then broke up, but Adams wanted to win her back.

After Bellisario landed a role in "Pretty Little Liars", Adams got himself a bit-part and stunned her at the script read-through.

The pair got back together, became engaged in 2014 and got married in 2016.

On Markle and Engelson's Divorce

On her defunct lifestyle blog The Tig, Prince Harry's wife posted a shady quote about hypocrisy which led fans to think she was alluding to Engelson.

Morton claimed that Markle just wanted out of her marriage out of the blue and did not explain her decision to her former husband. Engelson was reportedly taken aback when Markle returned her ring to him.

Markle and Prince Harry met in London 3 years after the divorce and were introduced to each other by a common friend.

Markle's Wedding Guests

Jessica Mulroney's three children were present as bridal attendants in Markle's wedding. She is reportedly Markle's best friend and is a Canada-based fashion stylist who worked for Canada's first lady Sophie Grégoire-Trudeau.

Her group gives a new light to the term power squad from her old college friends to Hollywood A-listers.

Meghan Markle's "Suits" castmate Gabriel Macht was in attendance with his wife, actress Jacinda Barrett. Adams was present with his wife, Bellisario.

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