AceShowbiz - Lynne Marie Stewart, a beloved actress distinguished by her iconic role as Miss Yvonne in "Pee-wee's Playhouse" and as the recurring character Bonnie Kelly in "It's Always Sunny in Philadelphia," has died at the age of 78.

Her passing was confirmed by her friend Cassandra Peterson, known for her role as Elvira, via an emotional Instagram post, "My heart is breaking upon hearing the news of my dear friend Lynne Stewart's passing. One of the kindest, sweetest, funniest women who ever lived. The iconic Miss Yvonne of 'Pee-wee's Playhouse:' She'll always be 'the most beautiful woman in Puppetland.' 💔”

A lifelong Los Angeles native, Stewart began her career in the comedy scene with the Hollywood-based sketch group, The Groundlings, where she bonded with talents like Peterson and Paul Reubens, who was later famed for his iconic role as Pee-wee Herman.

Stewart's character of Miss Yvonne, "the Most Beautiful Woman in Puppetland," debuted in the 1981 stage show "The Pee-Wee Herman Show". Fans also saw Stewart reprise her role in Pee-wee films such as "Pee-wee's Big Adventure" and "Big Top Pee-wee."

Stewart's versatile career also included roles in popular series like "M*A*S*H," "Night Court," and "Laverne & Shirley." She also appeared in films like "American Graffiti" (1973) and "The Running Man" (1987).

More recently, Stewart starred as Bonnie Kelly, the quirky mother of Charlie Kelly - played by Charlie Day - in "It's Always Sunny in Philadelphia," a role she carried from 2005 to her final appearance in 2023.

Stewart continued her passion for acting until the very end, having recently completed work on the upcoming comedy movie "The Dink" before being diagnosed with a tumor near her liver and gallbladder in December.

Bette Smith, her spokesperson, described the discovery and subsequent death as "quick and unexpected." Stewart's manager added, "She was a genius with her craft. The work was most important to her; she never cared about the money or fame. She was the kindest, most honorable person to know."

Comedy icons and fans alike have paid tribute to Stewart's remarkable life and career. "Gonna miss Lynne. Lynne Marie Stewart…So wonderful a spirit to work with on Sunny! All love to her family," shared Danny DeVito on social media.

Meanwhile, Charlie Day bid a solemn farewell, "The brilliant and talented Lynne Marie Stewart. Rest in peace. Thank you for all the years of laughter."

Stewart's warmth, humor, and unforgettable presence have left an indelible mark on the hearts of many. Though she is gone, the light she brought to the screen will continue to shine, forever echoing the joy she inspired.