Meghan Markle flew to Chicago to complete the processing of her UK visa.

The "Suits" actress is doing the necessary steps to become a permanent citizen of the United Kingdom. Markle was spotted in CFS Global UK Visa Application Centre in Chicago on Thursday, finalizing her application, TMZ reported.

According to eyewitnesses, Prince Harry's fiancée kept it low-key during the sighting. Markle attempted to remain incognito as much as possible. However, some still noticed her as she arrived with four bodyguards.

In addition, the entire office was cleared for her. In fact, the whole thing only took 10 minutes. Markle wore shades and a White Sox cap to blend in with the locals. She was friendly with the staff.

According to sources, the future royal forked over $1,500 for premium processing so she can get her visa within a few days. Based on the criteria, Markle most likely applied for a family visa and as partner or spouse.

Markle is marrying Prince Harry on May 19 at St. George's Chapel at Windsor Castle. Their wedding ceremony will start at 12 p.m. U.K. time (7 a.m. EDT). After an hour, the newlyweds will depart for the carriage procession.

As Prince Harry and Markle's nuptials draw near, the interest for the "Horrible Bosses" star has grown even more. In fact, a number of books featuring the future royal has been published. Princess Diana's royal biographer Andrew Morton released a biography titled "Meghan: A Hollywood Princess."

In his book, Morton compared Markle to the late Princess of Wales. However, many did not agree with the writer's assessment.

"How can Andrew Morton even try to compare Meghan to Princess Diana!!" Rachell Okin wrote on Twitter. "She wishes she was like her! Kate is following in Diana's footsteps far more. I don't see Harry & Meghan growing old together! What does Andrew actually know anyway!"

Leslie Carroll also published a book titled "American Princess: The Love Story of Meghan Markle and Prince Harry." Carroll talked with the actress' former classmates and teachers, who all have nothing but positive words to say about the princess in waiting.

Prince Harry and Markle will also be featured in a graphic novel "The Royals: Prince Harry & Meghan Markle." The book is published by U.S.-based TidalWave Productions. It will cover Prince Harry's involvement in the military, Markle's biracial background, divorced parents and acting career, as well as Princess Diana's death.

"Fans of the royal couple will love this issue for portraying Harry and Meghan as two well-rounded and grounded individuals," publisher Darren Davis said about the comics. "But it also has enough pomp and spectacle to match the excitement surrounding the event."