Pro Cantione Antiqua of London (PCA) is a British choral group which was founded in 1968 by tenor , counter-tenor Paul Esswood, and conductor and producer . Their first concert was at St Bartholomew's, Smithfield with Brian Brockless conducting but, from an early stage, they were closely associated with conductor and musicologist Bruno Turner. Arguably, they were the leading British performers of a cappella music, especially early music, prior to the founding of the Tallis Scholars. Singers have included:
* countertenors: Paul Esswood, , Geoffrey Mitchell, James Bowman, Keith Davis, Timothy Penrose, Kevin Smith, Michael Chance, Ashley Stafford, Richard Hill and Charles Brett.
* tenors: James Griffett, James Lewington, Ian Partridge, Ian Thompson and Andrew Carwood.
* basses: David Beavan, Ian Caddy, Brian Etheridge, Michael George, Christopher Keyte, Christopher Underwood, Stephen Roberts, David Thomas and Adrian Peacock.
* Though principally an all-male group it has been supplemented with female voices where appropriate (e.g. for the 1978 recordings OUP 151/2 under Philip Ledger, to accompany The Oxford Book of English Madrigals)

Strahil Popov (Bulgarian: Страхил Попов; born 31 August 1990) is a Bulgarian professional footballer who plays for Turkish Süper Lig club Kasımpaşa and the Bulgarian national team. He mainly plays as a right back. Popov began his professional career at Litex Lovech in 2008. After loan spells at Lokomotiv Mezdra and Montana he became a regular in their team, playing 159 total games and scoring 6 goals for Litex. He signed for Kasımpaşa in January 2016.

Ashley Nicolette Frangipane (; born September 29, 1994), known professionally as Halsey (), is an American singer and songwriter. After gaining attention from self-released music posted on social media platforms, Halsey was signed by Astralwerks in 2014. She released her debut EP, Room 93, later that year, and toured with larger acts to promote her music. Her debut studio album, Badlands (2015), debuted at number two on the US Billboard 200, and was certified Platinum by the RIAA. Its third single, "Colors", was certified Double Platinum.
Ashley Nicolette Frangipane (; born September 29, 1994), known professionally as Halsey (), is an American singer and songwriter. After gaining attention from self-released music posted on social media platforms, Halsey was signed by Astralwerks in 2014. She released her debut EP, Room 93, later that year, and toured with larger acts to promote her music. Her debut studio album, Badlands (2015), debuted at number two on the US Billboard 200, and was certified Platinum by the RIAA. Its third single, "Colors", was certified Double Platinum. Halsey rose to stronger prominence in 2016 as a featured vocalist on The Chainsmokers' single "Closer", which topped the charts of over ten countries. Her second studio album, Hopeless Fountain Kingdom (2017), debuted at number one in the US, and similar to her debut album, was certified Platinum in the country. The album consisted of more "radio friendly" music than her previous releases; its singles "Now or Never" and "Bad at Love" peaked in the top twenty of the US Billboard Hot 100, with the latter peaking in the top five. In 2018, Halsey released a single titled "Without Me", which became her first number one single in the US as a lead artist. Halsey is noted for her distinctive singing voice. Her music is categorized as indie pop ballads, usually based on her personal experiences. Her awards and nominations include four Billboard Music Awards, four iHeartRadio Music Awards, two Teen Choice Awards, one GLAAD Media Award, one Global Award, a Guinness World Record,, and a Grammy Award nomination. Outside of her career, she has been involved in suicide prevention awareness and sexual assault victim advocacy.

Strahil Popov (Bulgarian: Страхил Попов; born 31 August 1990) is a Bulgarian professional footballer who plays for Turkish Süper Lig club Kasımpaşa and the Bulgarian national team. He mainly plays as a right back. Popov began his professional career at Litex Lovech in 2008. After loan spells at Lokomotiv Mezdra and Montana he became a regular in their team, playing 159 total games and scoring 6 goals for Litex. He signed for Kasımpaşa in January 2016. Popov is a Bulgaria international, having represented his country at under-19 and under-21 level. He made his senior international debut in May 2014, aged 23, in a friendly match against Canada.