Seven songs into his headline show at Manchester's Co-op Live on September 25, Niall Horan stepped away from his regular set to offer the room an unexpected guest. Tom Ogden, frontman for Blossoms, walked out onto the arena stage to join the Irish singer for a duet of Charlemagne. Videos from the night showed the pair splitting vocals back and forth across the track, backed by an arena full of people shouting every word of the chorus straight back to the stage.

It was a notable collision between a major solo pop tour and regional guitar music. Charlemagne has served as the anchor of Blossoms' catalog since its first arrival back in 2015. When the band released their self-titled debut the following year, the track sat right at the beginning of the running order, helping carry that album straight to Number One in the UK charts. Under standard circumstances, Blossoms hold the song back until the very end of their own headline sets, reserving it as their traditional closer.

They did, however, change that routine quite recently. Last month, Blossoms marked the tenth anniversary of their debut record with an intimate Manchester concert at The Deaf Institute, running through the entire tracklist from start to finish. On that evening, Charlemagne opened the gig rather than ending it. Reflecting around that anniversary show, Ogden showed clear confidence about the staying power of the single that first established them. He pointed out that if they put Charlemagne out today, people would still jump on it. He joked that without it, perhaps they might have stayed at The Deaf Institute without evolving, though he added that he was going to back himself regardless.

The guest appearance at Co-op Live arrived in the middle of a busy schedule for Blossoms. The band is preparing for the release of their sixth studio record, Songs From The Wedding Cake, which arrives on October 2. That upcoming collection features Additional Driver, a collaborative track with Declan McKenna that was also played live during that intimate Deaf Institute performance. Following the album's release, Blossoms will head out on their largest headline tour so far. That itinerary happens to bring Ogden right back to the Co-op Live stage for two separate dates later this year, on November 28 and December 11.

For Horan, the Manchester date came during the opening week of his Dinner Party Live On Tour, which got underway on September 22 in Birmingham. Organizing an arena setlist of his own has involved balancing his solo catalog with his earlier work. Horan has previously discussed his approach to keeping One Direction songs in the mix, explaining that he felt it would do his former group a disservice if he left those tracks off the schedule entirely. He noted that wanting to play great songs made drawing from his old band a natural move, singling out Steal My Girl as a song that had been robbed of its day in the sun.

From Manchester, Horan takes the tour north to Glasgow's OVO Hydro on September 28, with subsequent dates scheduled for Sheffield's Utilita Arena and The O2 in London before the production crosses over into mainland Europe. The schedule eventually circles back for a pair of nights at Dublin's 3Arena on November 9 and 10, before coming to a close at Belfast's SSE Arena on November 15. Bringing Ogden onstage in Manchester provided a brief, unpretentious detour on the arena calendar, showing how comfortably a memorable guitar single can sit inside an evening of modern pop.