In 2004, she began starring as the lead character Addie Singer in the Nickelodeon series Unfabulous, which debuted in September of that year. The sitcom earned Roberts several Teen Choice Award and Young Artist Award nominations. The series focused on a seventh grader, Addie, and her two best friends. It aired for three seasons (2004–2007). The show also spawned TV movies, including The Perfect Moment. Also in 2004, Roberts guest starred in an episode of the Nickelodeon series Drake & Josh titled "Honor Council". After her run on Unfabulous, Nickelodeon had considered giving Roberts a kick start into a music career. In 2006, Roberts returned to the big screen, starring alongside Sara Paxton and singer JoJo in Aquamarine. She won a 2007 Young Artist Award for Best Supporting Young Actress in a Feature Film for her role in the film. The film Aquamarine took fifth place at the box office in its opening weekend making $8 million. In early 2006, Roberts finished shooting her title role in Nancy Drew. The film was released to theaters on June 15, 2007, and grossed over $7 million in its opening weekend, though the film was not well received by critics. Roberts was set to reunite with Nancy Drew director Andrew Fleming on both Rodeo Gal and a Nancy Drew sequel in 2007, but these films were never made.
In 2005, Paxton spent three months working on the Florida-themed Aquamarine, in which she played the title character as a mermaid, opposite Emma Roberts and JoJo, whom she befriended while filming. Paxton has said that she felt a sense of "female empowerment" while on set because "almost everyone" on set was female. The film opened on March 3, 2006 and grossed approximately $7.5 million in its opening weekend. Reviewers of the film compared Paxton, whose inspiration is Goldie Hawn, to actress Reese Witherspoon, saying that she has an "infectious, nutty energy." Paxton recorded a song for the film's soundtrack titled "Connected", an English version of the Mexican group RBD's song Tenerte y Quererte from their 2004 album Rebelde.
Aquamarine is a 2006 American teen fantasy comedy film directed by Elizabeth Allen, loosely based on the 2001 young adult novel of the same name by Alice Hoffman. It stars Emma Roberts, Joanna "JoJo" Levesque, and Sara Paxton. The film was released in the United States on March 3, 2006, by 20th Century Fox.
In 2004, Kebbel made her film debut portraying a major supporting role alongside Kevin Hart, Tom Arnold and Snoop Dogg in the hip-hop comedy film Soul Plane. She has also had numerous notable roles in films such as Be Cool, The Kid & I, American Pie Presents: Band Camp and Reeker. In 2005, Kebbel was announced to portray the role of Carrie Schaeffer alongside Sophia Bush, Brittany Snow and Jesse Metcalfe in 20th Century Fox's John Tucker Must Die. Filming took place in Port Moody, British Columbia, Canada during the summer of 2005. The film received negative reviews from critics and made a profit at the box office earning worldwide $68,821,702. In 2005, Kebbel signed on for another 20th Century Fox film titled Aquamarine starring Sara Paxton, Emma Roberts and Joanna (JoJo) Levesque. Kebbel portrays the role of the film's villain, Cecilia Banks. The film was released in March 2006, and had some box office success, with earnings of $23 million worldwide. In February 2006, Kebbel was confirmed to be starring alongside Sarah Michelle Gellar and Teresa Palmer in The Grudge 2. The film is a sequel to the 2004 Horror film, The Grudge which was a remake of the original Japanese film. Kebbel described her role of schoolgirl Allison Flemming as "The girl you see in the background of all the pictures that wants to be a part of everything but never really is". Filming took place in Tokyo, Japan, in April that same year. The film was released on October 13, 2006. The film was a box office success, grossing over $70 million worldwide.
In 2006 JoJo was cast opposite Emma Roberts and Sara Paxton in Aquamarine, playing Hailey. The film opened on March 3, 2006, opening at number five with $7.5 million. Her second major film, RV, a comedy starring Robin Williams, was released on April 28, 2006. It opened at number one and grossed $69.7 million. JoJo had to audition for the part five times, and eventually replaced an actress who had already been cast in the role. JoJo's second album, The High Road, was released on October 17, 2006. The album debuted at number three on the Billboard 200, selling 108,000 units. It was produced by Scott Storch, Swizz Beatz, J. R. Rotem, Corey Williams, Soulshock & Karlin and Ryan Leslie. It received mainly positive reviews. In the summer of 2006, the lead single from her second album, "Too Little Too Late", was released to radio stations. "Too Little Too Late" broke the record for the biggest jump into the top three on the Billboard Hot 100 chart, moving from number 66 to number three in one week; this record was previously held by Mariah Carey with her 2001 single "Loverboy", which went from number 60 to number two. The album's second single, "How to Touch a Girl", experienced less success. It charted just outside the Billboard Hot 100 and peaked at number 76 on the Billboard Pop 100. "Anything", was released as a third single to little success. The album sold over 550,000 copies and was certified gold by the RIAA in December 2006.
Aquamarine (2006): the title character is a mermaid (Sara Paxton) who is washed ashore after a violent storm. She decides to search for true love on land, and makes two good friends (Joanna "JoJo" Levesque and Emma Roberts) along the way. The film, loosely based on a children's book of the same name by Alice Hoffman, and directed by American director Elizabeth Allen, was filmed in Queensland, Australia. There were three different tails used in the production, including an animatronic model that was operated remotely. At least one of the others was a fully swimmable tail worn by the actress.