The band promised fans that the follow-up to 2010's Come Around Sundown will be released "sooner rather than later".
"We are in the writing process right now and it's coming along pretty quickly," bassist Jared Followill told BBC 6 Music.
"We'll definitely get into the studio but you know we have no plans of finishing it this year but definitely early next year, so I think people should expect something from us sooner rather than later."
The announcement follows a turbulent time in the band after frontman Caleb Followill walked off stage at their Dallas show last year, which consequently led to their US tour being cancelled.
The singer was diagnosed as too ill and exhausted to tour, so the gigs were never rescheduled.
Earlier this year, Jared Followill announced plans to release EP1 under his side-project Smoke & Jackal.
Watch the music video for Kings of Leon's 'Sex On Fire' below: