The Four Heavenly Kings are four Buddhist gods, each of whom watches over one cardinal direction of the world.
 In Chinese, they are known collectively as the "Fēng Tiáo Yǔ Shùn" () or "Sì Dà Tiānwáng" () in the ancient Sanskrit language they are called the "Chaturmaharaja" (चतुर्महाराज), or Caturmaharajikadeva: Four Great Heavenly Kings.
 The Hall of the Heavenly Kings is a standard component of Chinese Buddhist temples.
Andy Lau Tak-wah, BBS, MH, JP (, born 27 September 1961) is a Hong Kong actor, singer, lyricist and film producer.
 He has been one of Hong Kong's most commercially successful film actors since the mid-1980s, performing in more than 160 films while maintaining a successful singing career at the same time.
 In the 1990s, Lau was branded by the media as one of the Four Heavenly Kings of Cantopop.
Aaron Kwok Fu-shing (born 26 October 1965) is a Hong Kong singer, dancer and actor.
 Active since the 1980s, Kwok is considered one of the "Four Heavenly Kings" of Hong Kong.
 Kwok's onstage dancing and displays is influenced by Michael Jackson.
 While most of his songs are in the dance-pop genre, he has experimented with rock and roll, ballad, rock, R&B, soul, electronica and traditional Chinese music.
Janice M. Vidal (born 13 April 1982) is a Hong Kong Cantopop singer of mixed Chinese, Filipino and Korean descent.
 Vidal was first discovered by music producer Mark Lui and initially began her career as a back-up singer for Leon Lai.
 She debuted as a solo artist in 2004 under Lai's label, Amusic, where she remained until signing with Warner Music in 2015.
This is the discography of Taiwanese Mandopop artist Show Luo ().
 From 1996 to 1998, he was part of a quartet boy band "Four Heavenly Kings" (四大天王), releasing five albums.
 Then in 1998, after two members left, he formed a duo "Romeo" (羅密歐), with Ou Han Sheng (); the other member of "Four Heavenly Kings", released two albums and was active till 2000.
 In 2003, he debuted as a solo artist with the release of "Show Time".
 He has since released eleven Mandarin studio, one Japanese studio, three compilation, one remix and three concert DVD albums.
Leon Lai-ming, BBS, MH (born 11 December 1966) is a Chinese-born Hong Kong actor and Cantopop singer.
 He is one of the "Four Heavenly Kings" of Hong Kong.
 He uses the stage name "Li Ming" or "Lai Ming" which literally means "dawn."
Four Heavenly Kings (四大天王) is a Chinese term created in June 1992 by "Oriental Daily News" to refer to the four biggest male entertainment/arts superstars in Hong Kong at that time: Jacky Cheung, Andy Lau, Aaron Kwok and Leon Lai.
 Having successful singing (in both Cantopop and Mandopop) as well as acting careers well into the 2000s, they dominated the industry in Hong Kong and throughout the larger Chinese speaking world in the 1990s.
 Thus is the '90s is sometimes also called the "Four Heavenly Kings Era" in Hong Kong entertainment, as their songs swept the awards of Top 10 Songs of the Year during a 6-year span.
Forever Friends () is a 1996 Hong Kong released Taiwanese war-comedy film directed by Kevin Chu, starring Taiwan's popular "four little heavenly kings" (Nicky Wu, Takeshi Kaneshiro, Jimmy Lin and Alec Su).
 The original Taiwanese version of the film in Mandarin Chinese language was released in 1995 under the title "號角響起" (pinyin: Hao jiao xiang qi) which literally translate to "sounded horns".
 With the raising popularity of the "four little heavenly kings" in Hong Kong, the film was dubbed in Cantonese and renamed to a more comical title which literally translate to "four not normal youngsters" in order to cater more to the Hong Kong audiences.
The Hall of Four Heavenly Kings or Four Heavenly Kings Hall (), referred to as Hall of Heavenly Kings, is the first important hall inside shanmen (mount gate) in Chinese Pure Land Buddhist temples and Chan Buddhist temples and is named due to the Four Heavenly Kings statues enshrined in the hall.
Jacky Cheung Hok-yau (born 10 July 1961) is a Hong Kong singer, songwriter and actor.
 With more than 25 million records sold as of 2003, he is regarded as one of the "Four Heavenly Kings" and has been deemed the "God of Songs" of Hong Kong.

Question: What artist started as a backup singer for one of the "Four Heavenly Kings" of Hong Kong?
Answer: Janice M. Vidal