Before Betty Lynn became Thelma Lou, she was a proud patriot who entertained our troops.

The actress, who was best known for playing Barney Fife’s sweetheart on "The Andy Griffith Show," passed away in October 2021 at age 95. She had been working on an autobiography before her death, which was released posthumously on Monday. The book, titled "Becoming Thelma Lou – My Journey to Hollywood, Mayberry, and Beyond," was co-authored by pals Jim Clark and Tim McAbee.

Becoming Thelma Lou - My Journey to Hollywood, Mayberry, and Beyond

The late star's memoir, "Becoming Thelma Lou - My Journey to Hollywood, Mayberry, and Beyond," was published on Monday, Aug. 29, 2022. (BearManor Media)

McAbee told Fox News Digital that one of Lynn’s proudest achievements from her decades-long career was that of a performer as part of the USO Camp Shows. She started in 1944 and took her talents overseas, performing in the USO for service members during World War II. She was "thought to be the only American woman to have traveled the dangerous Burma Road during the war," according to a statement from The Andy Griffith Museum in Mount Airy, North Carolina.

Betty Lynn WWII

After graduating from high school, Betty Lynn traveled overseas to entertain American troops. (Courtesy of Tim McAbee)

"I was in awe of hearing her stories," said McAbee. "This was a young lady straight out of high school who put herself in very difficult situations. She chose to travel and perform for soldiers and visit them in hospitals. All she wanted to do was try and cheer them up. It didn’t matter if she found herself in harsh terrains or if temperatures were over 100 degrees. She was a very proud [patriot] and wanted to serve in any way she could. And she was just as proud of that as anything else she did in Hollywood, if not more."

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In her memoir, Lynn recalled how at age 18 she reached out to perform for the USO Camp Shows but needed her mother’s permission to join. While the matriarch was wary of her young daughter heading overseas, Lynn reminded her that "if I were a boy, they would make me go."

"I was very patriotic, as most people in those days were, and I wanted to do something for the war effort," Lynn wrote. "I convinced Mother that this was what I wanted to do. Even though Mother was very scared for me… she signed the papers allowing me to join the USO."

Betty Lynn USO

Tim McAbee said he was "in awe" of hearing Betty Lynn's memories of her time in Asia during WWII. (Courtesy of Tim McAbee)

Lynn’s conditions were far from glamorous. Lynn recalled how in Casablanca, Morocco, she "shared a dingy room" with a violin player where she slept on "a tattered mattress on the floor" that was "stuffed with straw and smelled of urine." Still, Lynn said she was determined to meet the soldiers who were defending her country. She went on to make stops in Cairo, Tehran and Karachi, among others.

At one point, she traveled on bridges made of bamboo and rope following a "monsoon-like downpour." She even described how a Marine captain gave her "a blue steel .32 automatic pistol and a shoulder holster" — just in case. Meals consisted of bread, which often became infested with insects, as well as oranges, bananas and coffee.

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"At this point in our touring, we were not just visiting hospitals," Lynn explained. "Wherever there were even a couple of servicemen, we would be sent to visit. In part, because everything was so unpredictable from day to day, our itinerary was not very organized. It was a matter of performing wherever we were needed or wherever we happened to be at that time."

Betty Lynn patriot

Betty Lynn slept with a gun under her head as she toured Asia with the troops. (Courtesy of Tim McAbee)

"I swam in the Salween River," she later shared. "Actually, I didn’t exactly swim in it per se, because I can’t swim, but I bathed in the river while wearing my clothes. If I had to go to the bathroom, somebody would have to check out the latrine, and then let me in and stand guard to ensure my privacy. To give me a shower, the men poured buckets of water over me, but I was dressed."

McAbee said it was important for Lynn to remember the soldiers she befriended during her travels in Asia.

"She explained to me that she was always patriotic," he said. "She loved her country. She wanted to do her part. And she chose to go. Even towards the end of her life, she would become emotional just talking about those hospital visits. She would describe how she would meet one soldier at a hospital, but the next day, when she returned, that soldier was no longer there. He had passed. It always made her incredibly sad."

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Betty Lynn American soldiers

Decades later, Betty Lynn was brought to tears remembering the soldiers she encountered along the way. (Courtesy of Tim McAbee)

Life for Lynn would later take a completely different turn. After World War II ended, she moved to New York and began acting. Her first credited role was 1948’s "Sitting Pretty." She also befriended top stars, such as Bette Davis and Maureen O’Hara, as she appeared in numerous films during Hollywood’s golden era.

"Five different studios asked her to screen test for them," said McAbee. "She ended up going with Fox. Still, she felt like she didn’t fit the typical mold of a Hollywood starlet. She was a redhead with freckles. She was much more the girl next door, something that she embraced. I don’t think she felt pressured to become a blonde screen siren. She knew who she was, and she owned that."

A casting call from an agent would lead to a role that would forever change her life. According to McAbee, Lynn instantly bonded with Andy Griffin and Don Knotts, her co-stars on "The Andy Griffith Show." The sitcom, about life in Mayberry, North Carolina, aired from 1960 until 1968.

Betty Lynn sitcom

Betty Lynn said entertaining American troops was one of her proudest achievements. (Courtesy of Tim McAbee)

"She loved them both dearly, and it developed into lifelong friendships," he said. "She especially had a close friendship with Don Knotts. They would meet up regularly and go to dinner. Betty also became very close with Don’s wife. Later in life, they even lived close to each other. So Don and [his wife] Frances would swing by and pick up Betty. It would be the three of them, going off to dinner and spending time together. As Betty and Frances would happily chat away, Don would sit there and just listen, occasionally chiming in with a word or two. But it was an incredibly close friendship. And she adored Don."

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Knotts passed away in 2006 at age 81. Lynn was devastated.

"Losing him was incredibly difficult for her," said McAbee. "There was a period of time when we were working on the book, and she had to stop. She put it on the back burner for a while because it was too painful for her to talk about Don. She missed him greatly. Some of her favorite memories that she recalled in the book about filming the show always included Don Knotts."

Betty Lynn Andy Griffith Don Knotts

From left: Betty Lynn as Thelma Lou, Andy Griffith as Andy Taylor and Don Knotts as Barney Fife in 1986's "Return to Mayberry." (Frank Carrroll/NBCU Photo Bank/NBCUniversal via Getty Images via Getty Images)

In 2007, Lynn moved from Hollywood to Mount Airy following a series of break-ins. In her later years, she participated in reunions with fellow cast members and became a fixture at Mayberry-themed festivals.

"She loved meeting with fans and hearing their stories of how much the show meant to them," said McAbee. "She totally embraced it and took her role very seriously. Her life was filled with gratitude, and she always expressed that. She only missed LA for her friends, not LA itself."

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"She enjoyed visiting the museum regularly and did so once a month. The people of Mount Airy not only embraced her back, but they made sure she was well taken care of. They made sure she had everything she needed. She truly loved everyone who took the time to come meet her. Her lines at autograph shows were always the slowest moving. She made sure every person who wanted to meet her had a moment to talk with her. And it was important for her to let them know just how appreciative she was."

Betty Lynn Don Knotts

Betty Lynn had a close bond with co-star Don Knotts. (Frank Carrroll/NBCU Photo Bank/NBCUniversal via Getty Images via Getty Images)

McAbee said Lynn spent her final years working on her memoir while looking after her family. While she had some major relationships over the years, which she discussed in her book, she never married or had children. Two weeks before her passing, Lynn was making final revisions to her book.

McAbee said she would be pleased with its release today.

Betty Lynn

Betty Lynn, seen here during the 1950s, passed away in 2021 at age 95. (20th Century-Fox/Film Favorites/Getty Images)

"Betty Lynn loved to entertain — and she did just that in her life," he said. "But I hope that in reading her life story, people might adopt some of her lessons of gratitude, of giving back and counting one’s blessings in life. She never took anything for granted. She worked hard and was successful, but she was just grateful. She was passionate and found solace in her family and faith. I think we could all learn a lot from Betty Lynn."

The Associated Press contributed to this report.