We'll regret it in the morning. Or at least, we'll regret it by Christmas, or Valentine's Day, or Mothers' Day at the latest.
There'll come a time when we're a bit embarrassed about admitting we ever liked Rumer, such is her imminent ubiquity.
En route to this showcase-cum-victory parade, when her debut album Seasons of My Soul has been on sale for only 24 hours but is already No 3 in the midweeks, I bump into a friend who, when I hesitantly admit where I'm going, comments, "She's a bit Radio 2, isn't she?" Well, yes, she is. But the old Radio 2, not the groovy new one.
There's something inherently mumsy about what Rumer does, something that seems suited to a coffee morning circa 1975. It would be oh so easy to dismiss her as Loose Women fodder, and move along. One problem: she is amazing. Everything's set up for 31-year-old Sarah Joyce to "do a Duffy", or "an Amy", although Rumer's twist on the nouveau-retro thing is less about Stax soul and more about MFP easy listening. No wonder Burt Bacharach's a fan. When she sings "My name's not well known/ Don't see my face in Rolling Stone", you know it's only a matter of time.
Born in an expat colony in Pakistan, Joyce has led a peripatetic life, spending time in a hippie commune in the Dorset countryside and witnessing in south London while singing in obscure bands until, relatively late in life, she was spotted. Rumer's mentor, MD, keyboardist and co-writer is the wild-bearded Steve Brown, aka Glenn Ponder, leader and conductor of the house band from Knowing Me, Knowing You with Alan Partridge.
The Tabernacle, a converted church, is laid out like a supper club, which suits Rumer perfectly. And as soon as she opens her mouth, I realise I've never seen such an effortless singer. That natural smoky tone, with hints of Dusty, Dionne, Carole and Roberta, just seems to fall from her lips.
"If you look in my eyes you'll see sorrow rise and fall," she sings, and it's true. What she's got they used to call the blues. And more than any of the comparisons above, Rumer sounds like a reincarnation of Karen Carpenter – a fact to which she gives the nod in "Thankful": "and the radio's playing 'Superstar'...".
One thing she's still learning is stagecraft, but her lack thereof is disarming. And she's a hell of a songwriter. I could live without the religious conversion material like "On My Way Home" ("I see a fire-red sky/And I get down on my knees in praise and disbelief ... Oh my God, I am yours"), but "Thankful", with sketches of human life like "A lady cycles past, her hair in braids/As they're pulling down the awning on the train station café ...", could be straight out of Joni Mitchell's The Hissing of Summer Lawns.
By the time she encores with immaculate covers of Laura Nyro's "Stoned Soul Picnic" and Bacharach's "Alfie", it's clear this is a class act. The rise of Rumer is one of those moments when we need to get over ourselves, do the walk of shame with heads held high, and "guilty pleasures" be damned.
"Fifteen years up in this game," acknowledges Big Boi in the intro to his debut solo album, "and I know that you don't feel me." The man who has been very much the Other One in the Outkast partnership is humble enough to accept his place in the scheme of things, but confident enough to blow all that baggage out of the water with one of the hip-hop albums of the year.
At least, that's how it works on record, where Sir Lucious Left Foot: The Son of Chico Dusty sees him stepping out of the shadow of his stellar sidekick, Andre 3000. In person, however, he still seems to choke in the spotlight. Or he simply can't be bothered to try. In an exactly hour-long set, the man born Antwan Patton lumbers about in standard-issue hip-hop garms – baseball hat, gold chain, three-quarter-length shorts. No one expects him to be as superfly as Andre, but it only emphasises the gap in star quality between the two. Patton and his sideman go through the usual motions of wave-your-hands-in-the-air gesticulating and, though the tech-rap tinkling of "Shutterbug" and the pysch-soul reverie of "Shine Blockas" come through, the DJ drags tracks like "For Your Sorrows" and "General Patton" down to a dull thud.
He delves into the Outkast catalogue for "I Like the Way You Move", for which girls are invited onstage to shuffle awkwardly, as well as Stankonia cut "So Fresh So Clean".
Admittedly, with Andre too busy being a film star/fashion guru/whatever, this might be as close to the real thing as we're likely to get, but a cheesy "Ms Jackson" singalong only adds to the feeling of "here's what you could have won ...".
Simon catches up with Foals, and finds out whether Jay Z-approved Clare Maguire is worth the hype