Lorde's performance at Free Press Summer Fest was cancelled after flash flooding.

The 'Green Light' hitmaker took to Twitter to apologise to her fans who were waiting to see her at the event in Houston, Texas after the festival got called off due to the extreme weather conditions.

She wrote on the social media site: ''FPSF, i'm so sorry but they've cancelled the day due to this apocalypse-style weather which means we can't play for you tonight ...

''crying shame because me charli and tove had cooked up a cover of umbrella by rihanna for u lol (sic)''

Charli XCX's performance was also cancelled due to the weather.

She added in her own tweet: ''just been told that my set at fpsf has been pulled coz of the thunderstorm... i'm so sorry guys. gonna go cry outside beyonce's house now :( (sic)''

The cancellation of the festival was announced in a statement on the event's website.

They wrote: ''In planning FPSF, patron experience and safety is paramount. Festival organizers, in agreement with the Houston Police Department, Houston Fire Department, and the Mayor's Office of Special Events, are announcing that FPSF has been cancelled for the remainder of the evening. With intense weather systems continuing and a flash flood warning issued by the National Weather Service, Eleanor Tinsley Park is unsafe for the event to continue.

''Refunds of 50% of the base ticket price will be refunded for any tickets purchased with a credit card within the next 7-10 business days. Ticketholders who purchased tickets with cash at the FPSF Box Office will need to contact Front Gate Tickets and provide their wristband print ID to request their refund at support.frontgatetickets.com within the next 30 days. Ticketholders who purchased tickets today, June 4, will receive a full refund.''