They truly are the Nicest Kids In Town, they are the all-star cast that make up this amazing movie! Here's a little info on each of the people who portray the leading roles

Nikki Blonsky (Tracy Turnblad)
This was Nikki's first film role. A native of Great Neck, New York, she worked at the Cold Stone Creamery ice cream shop before making her star turn as Tracy at the age of 18. She is also working on her debut album
John Travolta (Edna Turnblad)
John returned to movie musicals after 30 years. He is best known for his roles in Grease, Saturday Night Fever and Pulp Fiction among others, and on the small screen as Vinnie Barbarino on the 70s sitcom Welcome Back Kotter
Michelle Pfeiffer (Velma Von Tussle)
A versatile actress, Michelle's many credits include Batman Returns, The Fabulous Baker Boys, Dangerous Liaisons, Ladyhawke and Grease 2. She was the voice of Tzipporah in the animated feature The Prince of Egypt and did a guest voice in The Simpsons episode "The Last Temptation of Homer" as Mindy Simmons
Christopher Walken (Wilbur Turnblad)
Christopher has appeared in over 100 films during his prolific 50+-year career. Among his many credits are Pulp Fiction, The Milagro Beanfield War, Man of the Year, A View To A Kill and Balls of Fury. He also made his directoral debut in 2001 and has won many awards for his acting work
Amanda Bynes (Penny Pingleton)
Amanda is a talented young actress who has done stage, TV and film work. She hosted Nickelodeon's The Amanda Show and is better known for her roles in She's The Man, Big Fat Liar and What A Girl Wants. She is also interested in fashion design and drawing and recently launched her own clothing line called "Dear"
James Marsden (Corny Collins)
James followed his success in Hairspray with 2 other 2007 hit films - Enchanted and 27 Dresses opposite Katherine Heigl. He also appeared in the X-Men trilogy as Cyclops and Superman Returns. A talented singer, he performed vocals in several episodes of Ally McBeal, Second Noah (where he also played guitar) and the commercial for Sarah Jessica Parker's fragrance "Lovely"
Queen Latifah (Motormouth Maybelle)
Born Dana Owens, she has released several successful rap albums and starred in the 90s sitcom Living Single She received an Academy and Golden Globe award nomination for her performance as Matron "Mama" Morton in Chicago and also appeared in Bringing Down The House, Scary Movie 3 and Last Holiday among others
Brittany Snow (Amber Von Tussle)
A star on the rise, Brittany acted in several TV shows such as American Dreams, Guiding Light, Law & Order: SVU and Nip/Tuck. Movie credits include The Pacifier and John Tucker Must Die. She also appeared in several music videos and provided a voice for the video game Kingdom Hearts II
Zac Efron (Link Larkin)
Zac bolted to superstardom (and into the hearts of teen girls worldwide) as Troy in the smash Disney movie High School Musical and its equally popular sequel. No stranger to TV, he has done roles on Summerland, Firefly, The Guardian and ER. He will be playing the role of Ren in a remake of the 80s film Footloose
Elijah Kelley (Seaweed J. Stubbs)
A dancer, singer and actor from Georgia, Elijah appeared in 28 Days and Take The Lead before taking on Hairspray. As a child, he appeared in many commercials and has also performed in a gospel band. His next big role is the lead in a bio pic of legendary Rat Pack member Sammy Davis Jr.
Allison Janney (Prudy Pingleton)
Allison is best known for her role as C.J. on the political drama series The West Wing, for which she has received numerous awards. Many of her first roles were in soap operas, but she has acted in films such as American Beauty, Private Parts and Drop Dead Gorgeous. She also provided the voice of Peach the starfish in the Disney/Pixar film Finding Nemo