According to an article in Hktopten, they had to brave the cold for the romantic scene in the bathtub at an English mansion.
They worked on the scene for eight hours straight.
Although there were heaters at the location, being naked in the water was not easy for them.
Because the bathtub was long and slanted, Amber Kuo looked like she was lying on Chi Lam's chest while being intimate and romantic with him.
Actually, off camera, Chi Lam had used his legs to prop up Amber Kuo's lower half of her body. They had to stretch and warm up multiple times for the scene.
Amber Kuo said, "Of course I had to stretch, the bathtub was deep and I could easily get hurt from lying there for several hours."
Chi Lam said, "She kept sinking below like the Titanic, so I used my legs to prop her up. It was very romantic above, very embarrassing below!"