Lily Allen proudly posted a picture of Kate Bush's show from the London Hammersmith Apollo last night.
Bush had asked fans not to take photos or film during the shows - and, unusually, for a modern concert, they respected her wishes.
She had said: "We have purposefully chosen an intimate theatre setting rather than a large venue or stadium.
"It would mean a great deal to me if you would please refrain from taking photos or filming during the shows.
"I very much want to have contact with you as an audience, not with iPhones, iPads or cameras. I know it's a lot to ask but it would allow us to all share in the experience together."
But mother-of-two Lily decided to bend the rules as she showed her 4 million Twitter followers a snippet from inside the theatre.
Despite this rule-breaking, the rest of the compliant audience appeared to respect Kate's wishes and no other pictures - other than official snaps - have been leaked.
Sophie Heawood of the Guardian, took to Twitter saying: "Perhaps the most extraordinary Kate Bush thing tonight - apart from her entire show - was that nobody had their phone out at all. No pics."
Kate Bush: Before The Dawn – a first look
It all started so normally. Kate Bush, barefoot and in black, sang into a microphone with a seven-piece band behind her. After her second song, Hounds of Love, she declared "I need a drink of water" and swigged from a bottle at the side of the stage.
This could have been any gig almost anywhere. Perhaps Bush had decided to abandon the lavish theatricals of her one and only tour 35 years earlier in favour of something more conventional.
But then, six songs in, everything changed.
A dancer leapt centre stage, manically spinning an object around his head. Confetti exploded into the auditorium, and a giant screen dropped in front of the stage and played a short film featuring an astronomer.
Here, at last, was the much-anticipated live performance of The Ninth Wave, Kate Bush's 30-minute sonic odyssey about a shipwreck from 1985's Hounds of Love album.
What followed were surely some of the most mind-bending images ever to find their way into a rock concert - huge billowing sheets making a seascape, a search-and-rescue helicopter buzzing over the audience and sailors in lifejackets brandishing hatchets and a chainsaw.
There was even a bizarre mini-play - with Bush's teenage son Bertie as one of the characters - about cooking sausages.
And in the midst of it all Bush herself was carried off by what can only be described as fish skeleton creatures. This was the stuff of nightmares.
Even lovers of Kate Bush's music - and the Hammersmith Apollo was packed with them - were not expecting something so off the chart.
It felt like an opera, am-dram, a movie and a West End musical rolled into one.
After a 20-minute interval, Bush was back with more stunning visuals to accompany a batch of songs - collectively known as The Sky of Honey - from the 2005 album Aerial.
A wooden puppet child wandered the stage as Bush sang at her piano. Giant projections of birds in flight filled the back of the stage while 16-year-old Bertie was back in the role of an artist at work on a huge canvas. He even got to sing a solo song, Tawny Moon.
The early songs from the late 1970s and early 1980s that made a Bush a household name were absent, but no-one seemed to mind.
Bush may not be the energetic 20-year-old who last performed on the same stage in 1979, but the 56-year-old singer has retained the power to entrance her audience. Among the cheers, some were moved to tears at this most unpredictable of comebacks.
After the three-hour show, thousands spilled out into a damp London night knowing they had witnessed something unique. It's likely that many will wake next morning feeling they have been not only to a gig, but squeezed in a trip to the cinema and the theatre as well.