This star, who appeared in the hit 1978 musical Grease, looked unrecognizable while recently out in Los Angeles.The 80-year-old actor, who once starred with John Travolta and the late Olivia Newton-John, was spotted running an errand in his silver Lexus sedan.He was clad in a white shirt, dark pants, a navy vest, and slip-on grey sneakers.His tufts of textured white-grey hair were cropped short, and he rocked stubbly grey facial hair. Following his role in Grease, he exited Hollywood and became a high school teacher.Can you guess who he is? This star, who appeared in the hit 1978 musical Grease, looked unrecognizable while recently out in Los Angeles The 80-year-old actor, who once starred with John Travolta and the late Olivia Newton-John, was spotted running an errand in his silver Lexus sedanHe's former actor Michael Tucci, best known for playing Sonny LaTierri in Grease.Sonny was one of the members of the T-Birds gang, which also included Doody (Barry Pearl), Putzie (Kelly Ward), Kenickie (Jeff Conaway), as well as Travolta's character, Danny Zuko.The movie-musical follows Danny, who is torn between his obligations to his crew and his growing infatuation with Australian transfer student Sandy (Newton-John), whom he reconnects with during his senior year of high school after they spent a romantic summer together.Grease, based on the 1971 stage musical, was a hit at the box office, becoming the highest-grossing film of 1978 and taking in around $396 million over time.Following his part in the beloved project, Tucci played law student Gerald Golden in the TV series The Paper Chase from 1983 to 1986.He later went on to play Pete Schumaker in It's Garry Shandling's Show from 1986-1990.In the 90s he appeared in the first four seasons of the TV drama Diagnosis: Murder, which premiered in 1993.In 2013 the entertainer played the father of Melissa McCarthy's Detective Shannon Mullins. He's former actor Michael Tucci, best known for playing Sonny in Grease Sonny was one of the members of the T-Birds gang, which also included Putzie (Kelly Ward, far left), Doody (Barry Pearl, second from left), Kenickie (Jeff Conaway, not pictured), as well as Travolta's character, Danny Zuko (far right) He was clad in a white shirt, dark pants, a navy vest, and slip-on grey sneakers His tufts of textured white-grey hair were cropped short, and he had a stubbly grey facial hair Following his role in Grease, he exited Hollywood and became a high school teacher He wore brown-framed eyeglasses during the outingHis talents also extended to the stage, with Tucci touring in the musical Chicago for three years.He was cast as Roxy Hart's husband Amos.The talented performer also starred as the Green Apple in Uta Hagen's play Destination.His first bit of success on Broadway saw him booked as the understudy for the roles of T-Birds Kenickie, Roger, and Teen Angel, according to Broadway World.And Tucci was an actor in the 1973 original production of Godspell at the Promenade Theatre.He's also been a teacher and theatre coach, working at St. Francis High School in La Cañada Flintridge, California.In 2014 he directed students in the play We're the Millers.