Horseplay

Horseplay is a 2014 Hong Kong action comedy film directed by Lee Chi-ngai and starring Tony Leung, Ekin Cheng and Kelly Chen. The film's Cantonese and Mandarin theme song, Why Not Tonight (不如今晚) and The Best Night (最好的夜晚) respectively, was adapted from Henry Mancini's It Had Better Be Tonight with Leung, Cheng and Chen performing. Leung and Chen performed the Mandarin version at the 2014 CCTV Lunar New Year Evening on 30 January 2014.

Synopsis from Wikipedia, CC BY-SA 4.0. Everything below written here.