Geraldine Estelle Halliwell-Horner (née Halliwell; born 6 August 1972) is an English singer, songwriter, author, and actress. She rose to prominence in the 1990s as Ginger Spice, a member of the girl group the Spice Girls. With over 100 million records sold worldwide, the Spice Girls are the best-selling female group of all time. Their slogan "girl power" was most closely associated with Halliwell and her Union Jack dress from the 1997 Brit Awards also became an enduring symbol. Halliwell left the Spice Girls in 1998, citing exhaustion and creative differences, but rejoined when they reunited in 2007.
In 1999, Halliwell released her debut solo album, Schizophonic, which produced the UK number-one singles "Mi Chico Latino", "Lift Me Up" and "Bag It Up"; the lead single, "Look at Me", reached number two. In 2001, she released her second album, Scream If You Wanna Go Faster; the lead single, "It's Raining Men", reached number one in the UK, the biggest hit of her career. "Scream If You Wanna Go Faster" and "Calling" were also top-ten singles. Halliwell's third album, Passion (2005), was preceded by the single "Ride It".
In 2010 and 2012, Halliwell was a guest judge on the seventh and ninth series of The X Factor UK, and in 2013, she was a judge on the seventh series on Australia's Got Talent. In September 2013, it was announced that Halliwell would return to the music industry in Australia with the release of her first solo single in eight years, "Half of Me". She has written two autobiographies, including If Only (1999), and a series of children's novels, including Ugenia Lavender.
Halliwell has appeared in films, including Spice World (1997), Fat Slags: The Film (2004), Crank: High Voltage (2009), The Crown with a Shadow (2021) and Gran Turismo (2023).