Photos: The stars of Sesame Street Julia, a new autistic muppet character, will join the cast of "Sesame Street" in April. The character was first introduced during the new Sesame Street and Autism: See Amazing in All Children Hide Caption 1 of 21

Photos: The stars of Sesame Street Sesame Street's original star Big Bird has led the show since its first episode in 1969. The 8-foot Muppet often doesn't understand what's going on but sets the tone for the show by never hesitating to find out. Hide Caption 2 of 21

Photos: The stars of Sesame Street "Sesame Street's" Muppet characters were originally intended to be support for the human cast, but test audiences responded so warmly to Bert and Ernie's sketches that the producers put Muppets in starring roles. The comic duo have been two of the show's most popular characters ever since. Hide Caption 3 of 21

Photos: The stars of Sesame Street Sonia Manzano played shop owner Maria for nearly 45 years before retiring in July. She also worked as a writer for the show. Hide Caption 4 of 21

Photos: The stars of Sesame Street Alan Muraoka is the owner of Hooper's Store. He also works as a performer on Broadway. Hide Caption 5 of 21

Photos: The stars of Sesame Street Alison Bartlett O'Reilly took the role of Gina, an assistant at Hooper's Store and babysitter for Elmo and Zoe. She joined the ensemble in 1987. Hide Caption 6 of 21

Photos: The stars of Sesame Street Bob McGrath was one of the first four human cast members on Sesame Street. He is known for his music and singalongs, although Bob can also tell a good story or two. Hide Caption 7 of 21

Photos: The stars of Sesame Street Christopher Knowings helps out at Hooper's Store. He was cast in 2006. Hide Caption 8 of 21

Photos: The stars of Sesame Street Emilio Delgado, who plays Luis, was the first human cast member. When something needs to be fixed, he is the man to call. Hide Caption 9 of 21

Photos: The stars of Sesame Street Ismael Cruz Cordova is a new addition as Armando. He's best known for his role in the CBS drama "The Good Wife." Hide Caption 10 of 21

Photos: The stars of Sesame Street Loretta Long has played Susan since the show's beginning. When Big Bird needed comforting, Susan was there to help, and she is known for her maternal instincts. Hide Caption 11 of 21

Photos: The stars of Sesame Street Nitya Vidyasagar joined "Sesame Street" as Leela. The recent addition has a background in theater performance. Hide Caption 12 of 21

Photos: The stars of Sesame Street Roscoe Orman has played Gordon, husband to Susan, since Sesame Street began. Orman's real-life son Miles joined the cast in season 17 as Gordon's son, solidifying Orman's role as a kind and caring father. Hide Caption 13 of 21

Photos: The stars of Sesame Street The Muppet Show made him a star, but Kermit the Frog had begun winning younger fans on "Sesame Street," explaining to kids that "It's Not Easy Bein' Green" for the first time in 1970. Hide Caption 14 of 21

Photos: The stars of Sesame Street Fifteen years passed between the premiere of "Sesame Street" and Elmo getting his big break in 1984. But since then, the furry red monster with the high-pitched voice has gone on to become arguably the show's most popular Muppet. Hide Caption 15 of 21

Photos: The stars of Sesame Street "Om nom nom nom" -- Cookie Monster's voracious appetite for his favorite chocolate chip treats have endeared him to viewers since "Sesame Street's" first season. He's even managed to fit in teaching some important lessons: Thanks to him, generations of kids have grown up knowing that "C" is for cookie. Hide Caption 16 of 21

Photos: The stars of Sesame Street A bad-tempered green monster who loves "anything dirty or dingy or dusty" and lives in a trash can: perhaps not an obvious choice for a children's TV hero. Yet Oscar the Grouch, whose ambition is to be as miserable as possible, has failed to ruin viewers moods, bringing humor and fun to the Street. Hide Caption 17 of 21

Photos: The stars of Sesame Street Zoe broke into "Sesame Street's" largely male Muppet cast in 1994, becoming the show's stand-out female character. As she appears to be about the same age as Elmo, the two often spend time together. They are understood to be best friends. Hide Caption 18 of 21

Photos: The stars of Sesame Street Nothing can interrupt the Count when he's counting. Whether counting from one to 10 or up to a billion (as he did in 2013 to celebrate "Sesame Street's" 1 billion YouTube views), the Count is happiest with numbers. He can now count over 40 years of appearances on "Sesame Street" since his debut in 1972. Hide Caption 19 of 21

Photos: The stars of Sesame Street Is Grover the coolest Muppet on "Sesame Street"? He certainly thinks he is and describes himself as a "cute, furry little monster." Grover is one of the favorite creations of "Sesame Street" puppeteer Frank Oz, who said his generous personality and distinctive way of pronouncing each word "came about organically" when he brought the Muppet to the Street in 1970. Hide Caption 20 of 21