Nick Lachey will return to host next month's music competition on NBC, which features 16 a cappella groups - expanded from previous seasons - competing for the $200,000 and a Sony Music recording contract.
Each weekly episode will be two hours long.
As previously announced, singer Sara Bareilles will join Ben Folds and Shawn Stockman on the judging panel, replacing Nicole Scherzinger.
Watch last season's winners Committed being crowned in December below:
The new groups are:
A nine-person ensemble from Howard University, Washington DC which started as a class in the music department.
- The Cat's Pajamas
An all-male vocal group from Branston, MO that formed in 2005.
- The Collective
A first-time a cappella group of individual singer-songwriters from Nashville formed by Street Corner Symphony's Jeremy Lister, who appeared on the second season of The Sing-Off.
- Dartmouth Aires
Dartmouth College's oldest a cappella group consisting of 14 members.
This all-female a cappella group from Los Angeles features contestants from the first two seasons of The Sing-Off.
- The Deltones
A group of singers from the University of Delaware who have the motto 'friends first, singers second'.
- Fannin Family
This eight-piece group consists of relatives that come from Hortonville, WI.
- Kinfolk 9
This professional vocal group from LA has nine members who come from "strong musical backgrounds" and can all sing lead.
- Messiah's Men
This group hails from Africa but currently resides in Minneapolis. It consists of men who survived the war in Liberia through the power of song and "are on a mission to sing their hearts out while serving the Lord".
- North Shore
This "refined street corner group" has been playing together in the Boston area for the past 30 years.
Arlington's Pentatonix are a five-member group with "modern style" who count "several eclectic electro genres including dub step and garage house" as their influences.
This Los Angeles-based group formed in 2006 as a recording project that grew into a vocal band.
- Soul'd Out
This high school a cappella group from Wilsonville, OR have won awards in the past. It features students of all grades, musical backgrounds and vocal types.
- Urban Method
This group from Denver was formed by eight musicians, including a rapper, who favour urban music.
- Vocal Point
This nine-man group serves as the "premiere contemporary a cappella ensemble" from Brigham Young University.
- The YellowJackets
The University of Rochester's YellowJackets group formed back in 1956 and are known for their "distinctive sound" and bright yellow blazers. Half of the members are enrolled in The Eastman School of Music.
The Sing-Off returns on Monday, September 19 at 8/7c on NBC