Dr. Dre has produced several tracks for Snoop Dogg's upcoming album, "The Blue Carpet Treatment," due Nov. 21 via Doggystyle/Geffen. The new songs, which include "Imagine," will be the duo's first col

Dr. Dre has produced several tracks for Snoop Dogg's upcoming album, "The Blue Carpet Treatment," due Nov. 21 via Doggystyle/Geffen. The new songs, which include "Imagine," will be the duo's first collaborative effort in roughly five years.

"Imagine" finds the two longtime friends and collaborators ruminating about hypothetical situations such as life without hip-hop ("Imagine Russell [Simmons] still struggling/no Def Jam," Dre raps) and if Tupac Shakur never died.

"Blue Carpet" also boasts production from the Neptunes, Timbaland and Rick Rock, among others. Nate Dogg and Ne-Yo have joined the list of previously announced guest artists, which includes R. Kelly, Stevie Wonder, the Game and Ice Cube.

The disc will be the follow-up to 2004's "R&G (Rhythm & Gangsta): The Masterpiece," which bowed at No. 6 on The Billboard 200 and has sold 1.7 million copies in the United States, according to Nielsen SoundScan.