There were no graphic sex scenes or nudity involved, but it is still the most risque role she has taken on in her acting career since she debuted in the 2006 local film Becoming Royston.
Local TV and theatre actress Oon Shu An plays a Japanese porn star in upcoming local R21 film Rubbers.
The sex comedy required her to don a sexy cleavage-baring nurse outfit as well as lacy lingerie.
It also features her simulating oral sex on her male co-stars Alaric Tay and Chua Enlai.
The 28-year-old, who made headlines for landing a supporting role as a concubine in US TV series Marco Polo and is currently starring in Channel 5 legal drama Code Of Law 3, told The New Paper over the phone: "I had my reservations about the role, I was so scared. I didn't know what my parents would think."
She added: "Singapore can be quite conservative, so I wasn't sure how people would take it. My mum did ask me why did I have to take on the role and I told her not to worry as it would be done in a tasteful manner."
Oon, who prepared for Rubbers by watching Japanese adult videos prior to filming, said: "I didn't want to make a joke out of my character, so I did proper research. It was quite interesting to see and to understand that culture."
She attended a preview screening of Rubbers and said it is "touching and funny, and that it portrayed sex in a beautiful way".
Rubbers is helmed by local writer-director Han Yew Kwang and comprises three segments about love, sex and condoms.
The movie, which also features Yeo Yann Yann, Julian Hee and Marcus Chin, opens here on April 30 and is rated R21 for sexual content.
In Oon's segment, Tay portrays an irresponsible playboy who does not like to wear a condom during sex.