Singer Adele performs on stage at The O2 Arena on March 15, 2016 in London, England. Photo / Getty
"Baby, don't let the lights go down... I miss you when the lights go out." So sings Adele on I Miss You from her album 25.
But on Sunday the lights will go out on the 29-year-old from Tottenham as her mammoth world tour comes to an end with the last of four vast shows at Wembley Stadium.
By her own admission, it's the last we'll see of her for a while. Adele has been on the road for 16 months, playing over 120 shows from Sydney to Seattle.
According to some reports, she won't tour again like this for a decade. She herself has hinted that she'll be away for at least a couple of years, taking a much-deserved break and perhaps having a sibling for her son Angelo.
But while fans will have Adele's songs for succour during her absence, her sabbatical is likely to send shivers down the spine of the music industry. For the last two years, 25 has been the UK's best-selling album. Adele's concerts sell out in minutes.
She is one of British music's biggest exports since the Beatles. At a time when the music industry is grappling with changing consumption habits and a dearth of bona fide pop royalty, her star quality and bankability will be sorely missed.
An awful lot was riding on 25 for Adele when it was released in November 2015. Her previous album, 21, had sold 35 million copies. No pressure there, then. She understandably suffered a bout of writer's block, and entire sessions for 25 were scrapped.
The industry needed a hit too: physical album and download sales were falling rapidly and streaming had yet to fill the void, accounting for just a fifth of so-called album equivalent sales.
But a look at 25's statistics serves as a reminder of the phenomenon it eventually became. Things started on the evening of Sunday 18 October 2015 with a cryptic 30-second TV clip during an X Factor ad break. Soft piano chords played over a black screen. "Hello, it's me," sang one of the most distinctive voices in music, breaking 36 months of silence.
Adele's single Hello was released the following Friday. Within three days it had sold 165,000 copies in the UK. Within the first week it had been streamed 7.32 million times in this country alone. It became number one in 50 countries. 25 was released the following month, selling 800,000 UK copies in its first week, beating Oasis's record.
In the US it sold 3.38 million copies in its first week, and in so doing became - in a matter of days - 2015's biggest selling album. Adele achieved this without initially releasing the album on streaming services such as Spotify. As of February this year 25 had sold over 20 million copies, not quite as many as 21, but this campaign seemed far bigger because of the tour.
The Adele Live tour took in over 120 shows globally, including eight nights at London's O2, a headlining slot at Glastonbury and this week's concluding run at Wembley, which will break attendance records due to being held in the round. The Wembley shows are dubbed "The Finale", a neat nod to her beloved Wham!'s The Final concert, also held there.
Ed Sheeran, Adele's rival for chart dominance, only managed three Wembley Stadium shows two years ago (imagine her text to him), although this morning he announced two more for next summer (imagine his reply).
Over 25's campaign, Adele also won five Grammys. And five Brits. And the Ivor Novello for Songwriter of the Year. The money followed. According to Forbes, Adele earned $80.5 million in 2016 and $69 million in 2017 so far (equivalent to £117 million in total). As Adele herself acknowledged at the 2016 Brits: "Not bad for a girl from Tottenham who is scared of flying."
Success of this scale would be missed by any industry. But Adele did something more: she sold music to people who don't normally buy albums. According to research by Nielsen, 20 per cent of those who bought or intended to buy 25 in 2015 identified themselves as "non-music buyers".
According to Adelytics, a statistical research project about Adele by American University, four per cent of all the CDs sold in the US in 2015 were copies of 25. It sold an average of 122,000 CDs a day in the US across 2015, and it wasn't even released until late November.
Adele fans are therefore the industry's holy grail: they include many "bung it in the shopping trolley during the weekly shop" consumers, a tribe thought to be heading for extinction.
The singer also had a halo effect. Artists from Dolly Parton to Stormzy name-checked her in songs. People basked in her success and upcoming singers saw that they could make it too.
How will the industry cope? It won't. Not in sales terms. Sheeran will fill some of the void. Hopefully some of the UK's up-and-coming urban acts will too. Perhaps guitar music will make a comeback. Meanwhile, record execs will nervously gnaw their nails.
But Adele knows what she's doing. According to the Nielsen research, three-quarters of those who bought 25 said that the four years that had passed since 21 made them "want to buy it even more". This could be a long wait.