Joshua Scott "JC" Chasez (/ˈʃɑːzeɪ/; born August 8, 1976) is an American singer, songwriter, actor, dancer, and record producer. He started his career as a singer, actor, and dancer on The All-New Mickey Mouse Club before rising to prominence as a member of the boy band NSYNC in the late 90s and early 2000s. The band has sold over 70 million records, becoming one of the best-selling boy bands of all time. Chasez released his debut single "Blowin' Me Up (With Her Love)" in 2002, following NSYNC's decision to go on a hiatus earlier that year. Schizophrenic, his debut solo album, was released in 2004. Chasez has written and produced for a wide variety of music acts such as Liam Payne, Diplo, Backstreet Boys, McFly, The Cheetah Girls, Sugababes, Victoria Duffield, and Matthew Morrison. He also served as a judge on the first seven seasons of America's Best Dance Crew.

Joshua Scott Chasez was born on August 8, 1976, in Washington, D.C. When he was five years old, his biological mother entrusted guardianship of her son to her own former foster parents Roy and Karen Chasez, who worked as a technology company consultant and an editor, respectively. He was adopted by the couple who lived in Bowie, Maryland, and was raised Mennonite along with his younger siblings, Tyler and Heather. Chasez attended the former Robert Goddard Middle School and Bowie High School. He then got transferred to Dr. Phillips High School after moving to Florida to film The All New Mickey Mouse Club.

As a child, Chasez was extremely shy, but became interested in dance and got involved in competitive dance troupes. When he was 13, he entered a talent contest on a dare from a friend. He sang "Right Here Waiting" by Richard Marx and won first place. In 1990, his mother saw auditions for the Disney movie Newsies advertised in The Washington Post and encouraged him to try out. At the audition, Chasez was told that he was not the correct age for the character role they were casting for that day and was turned down. He was then told that there were auditions for Disney Channel's revival of The Mickey Mouse Club next door. After successfully auditioning for The All New Mickey Mouse Club, Chasez was cast as a Mouseketeer in the fourth season and subsequently moved to Orlando to film the show. He went by his initials because there was already another cast member named Josh (Ackerman). Chasez was on the show from 1991 to 1995, seasons 4 through 7. During his time on the show, he befriended future bandmate Justin Timberlake and performed alongside Christina Aguilera, Britney Spears, Keri Russell, Ryan Gosling, Rhona Bennett, and Tony Lucca. In 1995, it was announced that the show would not return for a new season.

After The All New Mickey Mouse Club, Chasez attempted to pursue a solo music career in Los Angeles, but decided to return home to Maryland after he was left feeling cheated. On his drive back he stopped at Justin Timberlake's house in Memphis, Tennessee, where they wrote demos together. Chasez and Timberlake eventually went to Nashville to continue writing songs and demo tracks with Robin Wiley, who had been a songwriter and vocal coach on The All New Mickey Mouse Club.

Timberlake then got a phone call from Chris Kirkpatrick, who was asking him to join what would become the boy band NSYNC. Timberlake decided to join the group and recommended Chasez as well. Chasez was still back home in Maryland saving up to return to Nashville. Together the three of them then decided to go to Orlando to look for a baritone. There they ran into Joey Fatone, who already knew Kirkpatrick from their time working together at Universal Studios Florida and was already acquainted with Chasez and Timberlake through friends from their time on The Mickey Mouse Club. After several auditions, the group recruited Jason Galasso as their bass singer. Timberlake's mother created the name NSYNC after she took the last letter of each of the initial members' names: JustiN, ChriS, JoeY, JasoN, and JC and commented on how "in sync" the group's singing voices were. After Galasso decided to permanently leave the group, he was soon replaced by Lance Bass.

Chasez and Timberlake served as the two lead singers of the boy band NSYNC. The group was formed in 1995 by Chris Kirkpatrick, and they began recording and performing the following year in Europe. In 1998, the band released its debut album *NSYNC which sold 11 million copies, earning them popularity in the United States with four number one singles including Tearin' Up My Heart and (God Must Have Spent) A Little More Time on You. After the band had a series of legal struggles with manager Lou Pearlman, they signed with Jive Records. They released their third studio album No Strings Attached in 2000, which became the fastest-selling album of all time, selling 2.4 million copies in the first week. They held this record until 2015 when Adele surpassed the single-week sales record with her third album 25. Singles from the No Strings Attached album include "Bye Bye Bye", "This I Promise You", and the number one hit "It's Gonna Be Me". The band produced their fourth studio album, Celebrity in 2001, which sold 1.8 million copies in the first week. NSYNC performed at the Academy Awards in 2000, the 2002 Winter Olympics, and the Super Bowl XXXV halftime show. The group sold more than 70 million records globally, making them the fifth-best selling boy band in history.

After their Celebrity Tour in 2002, NSYNC went on an indefinite hiatus but never formally disbanded.

While still a member of NSYNC, Chasez appeared on the remix and album versions of the 1999 single "Bring It All to Me" by the girl group Blaque, though his vocals were credited to NSYNC as a whole. During the band's time Chasez became involved with songwriting and production for his group and other artists, including Wild Orchid.