An electric storm threatened to bring the Glastonbury Festival to a halt before it had even started.
Organisers were forced to cut power to stages, halting dance collective Rudimental's set on the Pyramid Stage before 6pm.
A message on large screens at the Somerset Festival said that the organisers had stopped the performance as a safety measure.
"Thank you for your patience, we apologise for the inconvenience. In the interests of safety it was necessary to temporarily stop the show. Live music will return to the stage shortly."
The organisers managed to maintain their good humour despite fears that the weather might sabotage the first day of the festival.
The 90s track Sunshine On A Rainy Day by pop singer Zoe was played over the speakers as the large crowds waited for Lily Allen to take to the stage.
Rudimental, however, could not hide their disappointment.
"We're quite upset but we had a great time anyway," said Rudimental's multi-instrumentalist producer Amir Amor.
"We managed to shut down Glastonbury," he joked. "We called upon the Gods to have some lightning strike at the right time.
"Unfortunately, we had to get off the stage. They forced us off, which is a bit annoying, because we wanted to finish our set."
Writing on their Twitter page, Rudimental tweeted: "Thanks for an amazing experience #glasto, unfortunately lightning struck the stage and we were forced to finish our set early."
The band's DJ Locksmith added: "The weather broke my heart today... #glasto."
The band were allowed to return to the stage to take a bow, but missed the last two songs from their set list, including the number one single Feel The Love.
"We thought we were going to go back on," said keyboard player Kesi Dryden, "but unfortunately it was the end of our set.
"But before that it was an amazing show. We had a lot of fun and hopefully we can come back next year and give them our full set."
Live streaming of Glastonbury on the BBC website was interrupted by the storm just before 18:00 BST.
Once the storm had abated, the organiser's posted a celebratory tweet announcing: "The storm has passed. The sun is out. And all stages are running on schedule!"
Pop star Lily Allen stepped onto the main Pyramid Stage to cheers from the crowd at 19:00 BST, 30 minutes later than planned.
Kaiser Chiefs kicked off the first full day of music on Friday. Paolo Nutini is also expected to perform, while topping the bill this year are Metallica, Kasabian and Arcade Fire. Other acts scheduled to perform include Dolly Parton, Jack White, The Black Keys, Skrillex and Ed Sheeran.
Police said 85 crimes were reported within the first 48 hours of the festival opening its gates on Wednesday morning, a 30% decrease on last year. About half of these were property thefts, with 30 people arrested so far.
Meanwhile, one festival-goer has died after suffering a suspected reaction to ketamine. A 67-year-old woman also died of natural causes at the site.
Heavy rain is predicted everyday of the festival with revellers urged to come prepared with wellies and umbrellas.