All of a Sudden is a 1996 Hong Kong crime mystery film directed by Herman Yau and starring Simon Yam and Irene Wan.

An erotic mystery about a widower who seeks revenge against the man who had an affair with the widower's wife before her apparent suicide. However, things soon turn complicated when the widower begins a relationship with the man's wife.

• Simon Yam as Tsui Chin-tung
• Irene Wan as Lam Ho-yee
• Alfred Cheung as Lam Kwok-chiu
• Dayo Wong as Detective Guy Mak
• Peter Ngo as Bill Chan
• Tsang yin as Stella Tsui
• Lam Chiu-wing as Drunk driver
• Rico Chung as Driver in accident
• William Leung as Ming
• Lee Chi-kei as Solicitor Chan
• Joe Chu as Lam Kwok-choi's hired thug
• James Tsim
• Stephen Poon
• Kerrick Wong as Hard Rock Cafe staff
• Fong Yue as Sister Sam
• Wong Ka-on as Baby Lam
• Tam Wing-san as Uncle Wong
• Lo Hung as Security guard
• Mak On-luk as Policewoman

• List of Hong Kong films

• All of a Sudden at IMDb
• HK Cinemagic entry