Justin Cheung Kin Sing is a Hong Kong actor. Starting his career in HMV-produced erotic films, Cheung gained recognition with his lead role as Frankie in the erotic black comedy film Due West: Our Sex Journey (2012). He then transitioned to different genres, starring in the crime film Imprisoned (2015) and the drama film The Menu (2016). Cheung achieved breakout success with the role Jiu Jik in the crime thriller series OCTB (2017). He continued to star in various productions, taking on lead roles in crime films Deception of the Novelist (2019) and the Breakout Brothers trilogy (2021–2022), as well as supporting lead roles in ViuTV action thriller series Warriors Within (2020) and action film Dynasty Warriors (2021). He is set to reprise as Jiu Jik in the upcoming OCTB 2.

Breakout Brothers is a 2020 Hong Kong action comedy-drama film directed by Mak Ho-pong and starring Patrick Tam, Louis Cheung, Adam Pak and Justin Cheung as four prisoners who work together to plan their escape. The film was theatrically released on 3 December 2020 in Singapore and on 25 February 2021 in Hong Kong.