Geraldine Estelle "Geri" Horner (/ˈdʒɛəri/; née Halliwell; born 6 August 1972) is an English pop singer-songwriter, clothes designer, author and actress. Halliwell came to international prominence in the 1990s as Ginger Spice, a member of the successful girl group the Spice Girls; together they sold over 85 million records worldwide, making them the best selling girl group of all time. In 1998 Halliwell left the Spice Girls, though she rejoined the group when they reunited in 2007. Halliwell reportedly amassed a $40 million fortune during her last two years in the group.

In 1999, Halliwell launched her solo career and released her debut album Schizophonic, which spawned three number ones at the UK Singles Chart, "Mi Chico Latino", "Lift Me Up", and "Bag It Up", while the lead single "Look at Me" peaked at number two. In 2001, Halliwell released her second album Scream If You Wanna Go Faster; the first single, "It's Raining Men", peaked at number one in the UK and went on to become Halliwell's biggest hit of her career. She released her third studio album Passion in 2005. Halliwell has been nominated for four Brit Awards (in 2000 and 2002).

After a few years of relative obscurity, in April 2010, Halliwell announced that she had started working on new music. In April 2013, the Nine Network announced that she would become the fourth judge on Australia's Got Talent. On 12 September 2013, it was announced that Halliwell would return to the music industry in Australia with the release of her first solo single in nearly eight years, "Half of Me". With 11 number-one singles (seven as part of the Spice Girls and four as a solo artist), she is the female singer with the third-most number-one singles in UK Singles Chart history.