Harry Styles joins Niall Horan's concert, sings along to One Direction hit

One Direction fans were hit with a wave of nostalgia when Harry Styles made a surprise appearance at Niall Horan’s concert earlier this week.

On Tuesday, August 27, Styles, 30, was spotted in the crowd during his former One Direction bandmate’s The Show Live on Tour, jamming along as his former bandmate performed Stockholm Syndrome—a hit from One Direction’s 2014 album, Four.

In a fan-captured video circulating on social media, the As It Was hitmaker could be seen enjoying the performance at Co-op Live in Manchester, dressed casually in a yellow cardigan and white T-shirt, with a crossbody bag and some facial hair completing his laid-back look.

At one point, he even waves his arms to the rhythm of the song, clearly caught up in the nostalgia of the moment.

Four was the last album to feature all five original members of One Direction before Zayn Malik's departure in 2015, making this moment even more special for fans of the iconic boy band.

Horan, who released his third solo album The Show last year, is currently on tour with upcoming stops in Scotland, London, and Mexico City. The tour has already seen guest appearances from major artists like Ed Sheeran, who joined Horan on stage in Dublin.

Meanwhile, Styles has been keeping a low profile after a whirlwind few years, including the release of his album Harry's House and starring roles in Don’t Worry Darling and My Policeman.