Chasing the Dragon (Chinese: 追龍; Sidney Lau: Jui1 Lung4), previously known as King of Drug Dealers, is a 2017 Hong Kong action crime drama film directed by Wong Jing and Jason Kwan.

[2] The film is about an illegal immigrant from China who sneaks into British-colonized Hong Kong in 1963 and transforms himself into a ruthless and emerging drug lord.

Yen was convinced by Wong's sincerity to play a non-traditional role of a villain with limited fighting scenes and the opportunity to work alongside Andy Lau.

[6] It was a huge hit with audiences in most Mandarin-speaking parts of Asia (including China and Singapore), beating Hollywood blockbuster Blade Runner 2049 and Jackie Chan's The Foreigner, despite being marketed less heavily.

In Hong Kong, Chasing the Dragon earned more than 10 times the box office gross of The Foreigner.