Tom Meighan is leaving Kasabian by mutual consent.
The band has put out a statement saying the singer has been struggling with "personal issues that have affected his behaviour" for "quite some time".
They say he wants to "concentrate all his energies on getting his life back on track".
Kasabian first came to prominence in 2004 with the release of their first self titled studio album 'Kasabian'.
Within that time the band has amassed thirteen top 40 hits with four top ten records and Fire the bands biggest hit reached number 3 in the UK Top 40.
Just a few weeks ago Meighan had hinted to Sky News that work could begin on the bands seventh studio album as soon as lockdown was over. He also hinted at work on a solo album in the interview to.
Kasabian had been due to headline a gig at Leicester's Victoria park which was called off due to the coronavirus pandemic.
It remains to be seen whether the band will continue under the leadership of Sergio 'Serge' Pizzorno who himself had released his first solo work last year under the name SLP.