The band say they had ''no option'' but to pull out of the gig moments before they were due to go on stage at Custom House Square in the Northern Irish capital city on Tuesday night (22.08.17), because the frontman became poorly and was unable to stand up.
The 'God Bless This Acid House' hitmakers angered their fans by giving little notice, but have reassured them they will be rescheduling the performance and that the 36-year-old singer is resting up.
Taking to Facebook to reveal the illness which caused them to cancel the performance, the band wrote: ''Absolutely gutted to have to cancel last night's show in Belfast. We were all at Custom House Square, ready to go on stage when Tom suddenly went down with severe vomiting and could hardly stand up let alone sing. He was taken to hospital, put on a drip and told to rest up. We had no option but to cancel and we're sorry to our fans and anyone that travelled a long way. Thanks so much for all your messages of support. Details on the rescheduled date to follow soon xx (sic)''
Fans were urged to keep hold of their tickets as they will be valid for a rescheduled date when that is announced.
Last night a statement from the organisers read: ''We are working on scheduling a new date for Belfast. We will communicate with all ticket buyers via Ticketmaster and on the Custom House Square social media.
''Tickets remain valid for the new date. We apologise for any inconvenience caused.''
Many at the concert were outraged by the last-minute cancellation, claiming they had been waiting in the rain for hours and buying pricey drinks.
One fan tweeted: ''10 mins before your supposed to come on! I've been paying 5 quid pints for 2 hours! (sic)''
Another wrote: ''Why wait until 20:50 to tell the fans... we've been stood in the rain for nearly 3 hours! (sic)''
One supporter posted: ''Clearly not that buzzing for the gig tonight!! Fans standing in the p***ing rain waiting to see you's!! Bad craic lads (sic)''
That appeared to be referencing a tweet Kasabian sent out on Monday (21.08.17), which stated they were excited for the Belfast concert.
It read: ''Tokyo to Belfast, buzzing for tomorrow! (sic)''