Depot in the Castle has been cancelled due to the coronavirus pandemic.
The music festival was expected to return to Cardiff Castle on July 11 for its third year with Brit Award-winning band Kaiser Chiefs headlining.
However, the event will now take place at the iconic site on July 10, 2021, instead.
In an email sent to ticket holders, the organisers said: "We are sad to announce the inevitable postponement of this year's Depot in the Castle festival due to Covid-19.
"At this time of such unprecedented uncertainty we know that is the only way to ensure the safety of our artists, our staff and of course, all of you - our ticket-holders.
"Whilst we are absolutely gutted that we can't party with you all this summer, we are so looking forward to welcoming you back our iconic castle grounds when the time is right.
"Until then, we're sending good vibes to you all, from our homes to yours.
"Stay home, stay safe."
All tickets for the 2020 event will be automatically valid for next year. The artists due to perform have also been confirmed for 2021.
The likes of Basement Jaxx, Ella Eyre and Gentleman's Dub Club are some of the acts who will be joining indie rockers Kaiser Chiefs.
Along with live music there'll also be a wide range of street food vendors, bars and entertainment.
Last year saw the likes of Tom Odell and Clean Bandit perform over the weekend, along with a pre-event gig featuring Nile Rodgers and Chic at the same venue the day before.
Tickets for the event are still on sale and can be bought here.
