XO are a British girl group consisting of members Summer Askew, Shali Bordoni, Zoe Miller, Emmy Statham and Reanna Sujeewon. They were formed by Polydor Records in 2024 and released their debut single, "Lovesick", in September 2025. They later embarked on a headline tour across the United Kingdom, with another set for 2026. XO's first extended play, Fashionably Late, was released in November 2025.
Colin Barlow formed XO for Polydor Records in late 2024, choosing members Summer Askew, Shali Bordoni, Zoe Miller, Emmy Statham and Reanna Sujeewon. The members originate from Liverpool, Hong Kong, Essex, Derby and London, respectively. They have stated that they knew each other prior to being put in the group, from various auditions and projects they had done together. The members recalled their experience auditioning for the group, having seen a "very vague" advertisement in The Stage that read: "Can you sing and dance? Do you like the Pussycat Dolls?"; none of them knew what to expect and were shocked to be placed in a girl group by the end of the audition day. Miller stated that the audition was chaotic, with numerous people cut throughout the day after their singing and dancing.
In 2025, they embarked on a tour of schools across the United Kingdom, performing to schoolchildren and hosting discussions around mental health, body image and aspirations. Askew has admitted that the group were sceptical of the school tour, since they had no fanbase and little music to work with at the time. However, they became grateful for the experience since they found the travelling had helped them to bond. XO's initial release, "Ponytail", was released in August 2025, before their first official single, "Lovesick", a month later. "Lovesick" was written by Willow Kayne and Gracey. It was described by Clash magazine as a "titanic debut single" with "irresistibly catchy" arrangements that allowed each member of the group to introduce themselves, with Wonderland billing it a "pulsating electropop anthem".
XO made their television debut on the CBBC live magazine series Saturday Mash-Up! in September 2025. As well as performing "Ponytail", they also made a cameo on a sketch. Whilst receiving airplay from BBC East Midlands, where Statham is from, the station confirmed that XO's debut extended play (EP) would be titled Fashionably Late. In a piece written by the Sunday Times, they confirmed the release was scheduled for November 2025 and featured songs co-written by Charli XCX and Lostboy. "Real Friends", co-written by Charli XCX, was released as a single in October 2025. The song was produced by John Ryan and Mattias Larsson. XO embarked on their first headline tour across the United Kingdom in October 2025; it saw them perform all of the songs from Fashionably Late, as well as "Clique", an unreleased track. The EP was released on 14 November 2025. "Candy" became their third single on the day of the EP's release. December 2025 saw them release a cover of the Justin Bieber Christmas song "Mistletoe". In March 2026, they performed at the 2026 Gaydio Awards. Their performance included their debut of "Hot Girl Hotline", their next single. They are set to embark on their Fashionably Late Tour in May 2026.
XO have cited the Spice Girls, Tate McRae and Katseye as musical influences. They have also been likened to Blackpink due to incorporating the "new wave of all-choreo" into their performances, with the group stating that they always consider choreography whilst making their music. They were also likened to Sugababes for their "edge". Upon the release of Fashionably Late, they were compared to Gwen Stefani, the Pussycat Dolls, Fergie and Girls Aloud.