MusicXML scores for flute by Christina Aguilera

Christina María Aguilera ( AG-il-AIR-ə, Spanish: [kɾisˈtina maˈɾi.a aɣiˈleɾa]; born December 18, 1980) is an American singer, songwriter, actress, and television personality. Referred to as the "Voice of a Generation", she is noted for her four-octave vocal range, musical reinventions, sustaining high notes including use of the whistle register, and a signature use of melisma throughout her music. Recognized as an influential figure in popular music, she also became known for incorporating controversial themes such as feminism, sexuality, LGBT culture and the sex-positive movement into her work. Aguilera was also honoured as a Disney Legend, for her contributions to The Walt Disney Company.

After appearing on The All-New Mickey Mouse Club (1993–1994) as a child, Aguilera recorded "Reflection", the theme for the 1998 animated film Mulan and signed a record deal with RCA Records. She rose to fame in 1999 with her self-titled debut album and the US Billboard Hot 100 number-one singles, "Genie in a Bottle", "What a Girl Wants" and "Come On Over Baby (All I Want Is You)". Aguilera also won the Grammy Award for Best New Artist and followed with Mi Reflejo (2000) and My Kind of Christmas (2000); with the former becoming the best-selling Latin pop album of 2000. After gaining more control over her career, Aguilera sought a departure from her teen idol image and released Stripped (2002). Despite an initial mixed response, the album went on to become one of the best-selling albums of the 21st century. Aguilera underwent another reinvention with the release of the critically praised old-school-music inspired Back to Basics (2006). Throughout these periods, she amassed numerous international successes, including the number-one single "Lady Marmalade", alongside "Beautiful", "Dirrty", "Can't Hold Us Down", "Fighter", "Ain't No Other Man" and "Hurt".

Throughout the early 2010s, Aguilera had a moderately successful period with the albums Bionic (2010) and Lotus (2012), with their respective lead singles, "Not Myself Tonight" and "Your Body", topping the US Dance Club Songs chart. She also starred in the 2010 film Burlesque and contributed to its soundtrack, earning a Golden Globe Award nomination. Aguilera returned to the top of the charts with a string of collaborations, including "Feel This Moment", "Say Something", and "Moves like Jagger"; with the latter reaching number-one on the Hot 100, making Aguilera one of the few artists to reach the top spot over three decades. She found critical success with her follow-up albums Liberation (2018) and Aguilera (2022). Her concurrent ventures included a role in the series Nashville (2015), roles in the films The Emoji Movie (2017) and Zoe (2018), becoming an ambassador for the World Food Programme (WFP), performing two concert residencies and serving as a coach on the reality competition show The Voice (2011–2016).

Aguilera is one of the best-selling music artists of all time, with estimated sales of over 90 million records sold worldwide. Considered a pop culture icon and a triple threat entertainer, she has been named one of the greatest vocalists of all time by publications such as Rolling Stone and Consequence of Sound and has been hailed as one of the most successful artists to come out of the 2000s. In 2009, Billboard named her the twentieth most successful artist of the decade, and was ranked eighth on VH1's list of greatest women in music. Aguilera has since been regarded as one of the most influential Latin artists in the entertainment industry, having helped shape the "Latin explosion" in the music industry. Her accolades include five Grammy Awards, two Latin Grammy Awards, six ALMA Awards, two MTV Video Music Awards (VMA), one Billboard Music Award, one Guinness World Record, and a star on the Hollywood Walk of Fame.