The release date for 50 Cent's new album, "Curtis," has been bumped from June 26 to Sept. 4 to allow the artist more time to complete the tracks. So far, radio has been slow to pick up on the singles "Straight to the Bank" and "Amusement Park," which are Nos. 49 and 53 respectively on Billboard's Hot R&B/Hip-Hop Songs Chart.

As previously reported, "Curtis" also features production from Dr. Dre, Eminem and Timbaland, plus guest turns by Eminem, Akon, Justin Timberlake, Mary J. Blige, Robin Thicke and Nicole Scherzinger from the Pussycat Dolls. A track list has yet to be announced.

The new album is the follow-up to 2005's "The Massacre," which debuted at No. 1 on The Billboard 200 and Billboard's Top R&B/Hip-Hop Albums chart.

The promo blitz for "Curtis" is well underway, with videos for "Straight to the Bank" and "Amusement Park" already garnering airplay and a humorous new TV ad for Vitamin Water that finds 50 relieving a symphony orchestra conductor of his duties, installing DJ Whoo Kid on first viola and leading the musicians through a rendition of "In Da Club."

50 will also perform June 26 on the BET Awards, with fan text-message voting determining which track he will play.