2003–2008: The Cheetah Girls, 3LW disbandment, and acting career
Beginning in late 2002, 3LW held nationwide auditions for a new third member. Jessica "J" Benson was selected and with Benson, the group continued to promote A Girl Can Mack and began working on their third studio album. In June, 3LW departed from Epic Records and signed with So So Def.
Amidst 3LW's public drama, Bailon and Williams signed on to star in the Disney Channel Original Movie, The Cheetah Girls. They starred as two of four members of a girl group named after the film, with Raven-Symoné and Sabrina Bryan portraying the final two members. The movie premiered in August 2003. Upon release, the film was the number one rated basic cable telecast and premiered to 6.5 million viewers, a record for Disney at the time. The film's soundtrack was certified double platinum by the RIAA. In 2003 and 2004, Bailon had a supporting role on the second season of Disney Channel's That's So Raven in which she played Alana, a personal enemy of the show's title character. In 2005, she appeared as Dominique in Coach Carter, her first theatrically released film.
The success of The Cheetah Girls film prompted Disney to turn the project into a real girl group, composed of Williams, Bailon, and Bryan. Raven was offered a spot in the group but opted to focus on her solo career. Bailon noted that both The Cheetah Girls and 3LW projects would continue concurrently. As a trio, the Cheetah Girls began working on their first studio album, Cheetah-licious Christmas, which was released in 2005. Bailon then starred in the MTV film All You've Got, along with R&B singer Ciara. It was released on DVD in May 2006 and premiered on MTV.
The release of 3LW's third studio album, tentatively titled Phoenix Rising in 2003 and later Point of No Return in 2005, was delayed several times. On August 15, 2006, the group released the single "Feelin' You", but it did not impact any major charts. Point of No Return was shelved and Bailon and Williams continued with The Cheetah Girls. 3LW officially disbanded in 2007.
In April 2006, the Cheetah Girls began filming the sequel musical film The Cheetah Girls 2. Raven-Symoné returned for the film, which was shot on location in Barcelona, Spain. The Cheetah Girls 2 premiered on August 26, 2006, and received over 8.1 million viewers, making it the highest-rated premiere for a Disney Channel Original Movie at the time. The film's soundtrack album was certified platinum by the RIAA. The Cheetah Girls released their second studio album TCG on September 25, 2007, which featured the single "Fuego".
In January 2008, filming commenced on the third Cheetah Girls film,The Cheetah Girls: One World, in which the group appeared as a trio without Raven-Symoné. The Cheetah Girls: One World premiered on August 22, 2008 and its soundtrack was released on August 19. While the film was a ratings hit, debuting with 6.2 million viewers, the soundtrack failed to match the success of their previous soundtrack releases and sold 140,000 copies in its first two months. Bailon recorded the solo songs "Stand Up" and "What If" for the film's soundtrack album. In late December 2008, the group disbanded.