Rock City, also known as R. City and Planet VI, is a musical duo from Saint Thomas, U.S. Virgin Islands. The duo was formed in 2003 by brothers Theron Thomas and Timothy Thomas who used the stage names A.I. and Uptown AP respectively. The two are also a songwriting and record production team.

Thomas brothers grew up in the Oswald Harris Court Projects and graduated from Charlotte Amalie High School. They were backup dancers for a local all-girl rap group when they were kids. In 2000, the two left the Virgin Islands to pursue their music career in Miami, Florida. They initially operated under the name 2Ekwip. They had limited success in the Miami nightlife scene and moved back to Saint Thomas in 2005.

In 2006, the duo wrote "The Rain" for Akon's triple platinum-selling album "Konvicted". In the following year, they signed a record contract with Geffen Records and Akon's KonLive. They were then working on their debut album "Wake the Neighbors" which was originally set for release in 2008. The album was delayed and wasn't immediately given a new release date.

In 2011, the duo parted ways with KonLive and started their own label, Rebelution Records. While working on their own projects, they still penned songs for other artists. At this point, the brothers are perhaps best known for writing and producing hit singles for artists like Sean Kingston ("Take You There"), Miley Cyrus ("We Can't Stop"), Nicki Minaj ("Only") and Rihanna ("Pour It Up").

They have also made contributions to a number of Grammy-nominated albums including Rihanna's "Unapologetic" (which won Best Urban Contemporary Album), Jennifer Hudson's self-titled album (which won Best R&B Album) and Ariana Grande's "My Everything" (which was nominated for Best Pop Vocal Album).

In 2015, R. City released their own song "I'm That..." featuring 2 Chainz before storming the charts with "Locked Away" featuring Adam Levine. The latter song has so far peaked at No. 16 on Hot 100.