From the stage of the O2 Arena, Cher is giving a speech. It started out as an anecdote about her 40th birthday, but that was quite a long time ago. Since then, it has deviated from its initial topic to encompass everything from Madonna to former chatshow host David Letterman, to the fact that American schools no longer teach pupils to write in cursive script, to Donald Trump (“an asshole”) and Boris Johnson (“not much better”), before reaching the subject of Cher’s age. “People applaud when I say I’m 73,” she notes, “and I wonder if it’s because I’m still alive. Anyway,” she concludes with a smile, “what’s your granny doing tonight?”

To which the inevitable answer is: I’m not sure, but probably not standing on top of a giant mechanical elephant with illuminated tusks and eyes, singing a kind of AOR funk version of the ancient Sanskrit hymn the Gayatri Mantra, which is what Cher does next. The audience seems less startled by this turn of events than you might expect, but, in fairness, Cher has pulled the whole mechanical elephant with illuminated tusks/AOR funk version of the Gayatri Mantra trick before, during what was supposed to be her farewell tour, 14 years ago, and something about the sheer force of the crowd’s devotion makes you suspect they were probably there then, too.

Relentless visual bombardment ... Cher. Photograph: Ben Perry/Rex/Shutterstock

Reprise or not, it constitutes one of the more baffling interludes in a show whose title gamely alludes to her now outdated retirement by borrowing a line from Abba: Here We Go Again. Abba feature heavily tonight: three covers that bump any number of her own hits from the setlist, not least Gypsies, Tramps and Thieves, testament to the critical and commercial success of her 2018 album Dancing Queen. In fact, it’s big on latter-day, knowingly camp Cher full stop. You get a lot more Abba and Euro-disco oompah in the vein of her 1998 smash Believe than you do of anything else, including 80s power-ballad-on-a-battleship Cher – her guitarist, who appears to have arrived direct from the American Rock’n’Roll Guitarist department of central casting, only really gets to let rip on the home run of If I Could Turn Back Time and I Found Someone – and 60s pop-harbinger-of-the-counterculture Cher, although she sings I Got You Babe and The Beat Goes On as duets with her late ex-husband Sonny Bono, his voice coming out of the PA and his face in black and white on the video screens.

The setlist allows the glitzy spectacle to be turned up to Vegas show proportions. As you might expect, given the giant mechanical elephant with illuminated tusks, this is not a gig that prizes subtlety above all else: it’s the kind of gig during which music from the 70s is accompanied by dancers in afro wigs and satin flares, and music from the 60s is accompanied by ladies in black and white chequerboard mini-dresses, dancing in the way that ladies in black and white chequerboard minidresses always dance when required to signify the 60s.

If you were minded to pick holes in the enterprise, you might alight on the fact that there are a lot of interludes when Cher isn’t on stage at all – whole songs, including Bang Bang, are shown on the video screens rather than performed live – although, in fairness, there’s always something to keep your eyes occupied when she isn’t, from aerialists doing their vertiginous thing to footage of Cher performing Heartbreak Hotel dressed as 1968 Comeback Elvis, complete with stick-on sideburns.

And besides, it’s not the kind of enterprise you’re minded to pick holes in. When she is there, her voice sounds fantastic and she looks extraordinary; the visual bombardment is relentless and wilfully, stupidly, charmingly OTT. She mentions she had doubts about touring again, before deciding, “Bitch, you’re 500. Do it now.” A conclusion only a curmudgeon would say was wrong.