It was the smile and the wave right at the end that did it. It was only five seconds, but watching live, it felt like it was happening in slow motion.
In that moment, the nation fell in love with Sinead O'Connor again. And it happened - of course - on the 'Late Late Show'. It was a special, historical moment for the first show of the new season.
Scarlet-clad and barefoot, Sinead had just given an emotive performance of 'Nothing Compares 2 U', with its heartbreaking lyric: "I know that living with you baby was sometimes hard, but I'm willing to give it another try." It seemed to take on a personal significance as she made her comeback as a singer on the biggest show on RTÉ.
As the strings played the song out, she looked straight into the camera and gave a kind of giddy smile; a somewhat nervous wave of the hand, like a child might.
But there was something true about it, something sincere, that made it feel as though she was looking right through the television screen and at you.
I suddenly felt like crying. I was flooded with nostalgia for a moment that was happening in the here and now. It was cathartic. It was joyous. It was like: "Sinead! All is forgiven! We love you!" What the hell was she doing to me?
It is easy to forget momentarily what a powerful artist Sinead O'Connor is, amid all the drama. I find it impossible not to like her, although God knows, she makes it as difficult as she possibly can. She holds her wounds out for all to see, and dares you to look away.
She can be trouble-making and challenging, and prone to lashing out. But she is also extraordinarily endearing, alluring and disarming, and empathetic to a painful degree.
Most journalists love her, because she loves us. She has no snobbery in her. It's flattering when an international music star invites you to her home and keeps you there for the entire afternoon. She takes you to her shed and plays guitar, and you tell her things about yourself you haven't told anyone. You have to ring your editor and say: "Sorry about this, I've been kidnapped by Sinead O'Connor. We may or may not elope."
There was an irony in her sharing a 'Late Late' line-up with Maura Higgins from 'Love Island', who was risibly hailed as a feminist for sucking on an ice-lolly and telling a fella to "Go f**k yourself" on a reality TV show.
Maura sat on the couch like a preening doll, while Sinead, always the most beautiful woman in the room, wore a abaya dress and no make-up. Maura has built her career on the cosmetic - Sinead has spent a career trying to diminish her natural good looks.
She names Joan of Arc as her heroine and it's easy to see why she relates to the 15th-century martyr who was burned at the stake for "abominations" and for refusing to subject herself to authority.
Like the Maid of Orleans, Sinead has often been seen as mad for saying things that turned out to be true. She has always been ahead of her time, whether it be ripping up a picture of the Pope on US television to highlight clerical abuse, before the scandal came out, or refusing to bring politics into music, decades ahead of the culture wars that have allowed ideology to constrain artists. These were not publicity stunts: she paid the price at a time when such stances were punished, not praised.
When Miley Cyrus put on a porno performance at the VMAs in 2013, Sinead was ridiculed by some when she wrote Miley an open letter saying she was obscuring her talent by allowing herself to be pimped. But she was right: earlier this year, Miley told how she "felt sexualised" at the time.
Here's why Sinead is my heroine, a true feminist icon. She is a self-reliant alpha female, having four children by four different men, all chosen seemingly more for achievements and intellect, rather than being on an aesthetic pedestal. She speaks openly about her sexuality, which she has described as her "life force".
She is unconcerned by societal norms, marrying four times: "Clearly I'm a crap wife." She rejects labels, saying: "If I fall in love with someone, I wouldn't give a s**t if they were a man or a woman." Her song 'No Man's Woman' is one of the best songs about feminism and living a free life: "I don't want to be no man's woman, I've other work I want to get done."
She is performance artist, powerhouse, dissenter, heretic, theologian, trailblazer, truth-teller. She is feminine and fierce, daring, brave, raw and instinctive. She will not be knocked down.
It's time to honour Sinead O'Connor.