First, they played mother and son in 2013's award-winning film Ilo Ilo.
Six years later, Yeo Yann Yann and Koh Jia Ler are reuniting under director Anthony Chen for his second film, Wet Season.
This time, they'll be playing lovers.
Well, sort of.
Malaysian actress Yann Yann, 42, plays a married teacher, Ling, who starts to develop a relationship with her student Wei Lun (played by Jia Ler), culminating in a steamy bed scene between the two where the latter even bared his butt for the camera.
In a Skype interview yesterday (Sept 10) with local media, Yann Yann said there weren't any "challenges" because she was only "playing a role".
She was speaking from Toronto, along with director Anthony Chen, where the film made its world premiere at the Toronto International Film Festival (TIFF) and will compete in the Platform Competition.
To help Jia Ler immerse in the role, Yann Yann also instructed him not to call her 'Mum', which he had gotten used to on the set of Ilo Ilo.
She said: "I told him that we were now fellow actors."
Jia Ler, who made an appearance at the interview as he wasn't free to travel to Toronto, confirmed the matter, admitting that if he slipped up, he would get a scolding from Anthony.
The love scene took a day to film and according to Jia Ler, not only was it "a little awkward", he fumbled quite a bit.
He confessed that it was easier to film the wushu scenes in the movie than the love scene. Not surprising, considering that the 18-year-old has been practising wushu for the last decade.
Jia Ler also revealed that he doesn't have a girlfriend but did inform his mother about the scene. When asked if his parents had any issues with it, 35-year-old Anthony explained: "I've known his parents since he was 11 and they trust me."
WET SEASON ISN'T JUST ABOUT LUST
Wet Season is set in Singapore during the monsoon season and tells the story of Ling, whose life and marriage are breaking down because she's unable to bear a child. Her friendship with Wei Lun tides her through the frustrations and disappointments, eventually leading her to rediscover herself.
Anthony is aware that the teacher-student relationship is a sensitive topic in Singapore but hopes that the film won't be censored or slapped with an R21 rating.
He emphasised that the film explores many layers of the relationship between Ling and Wei Lun, and isn't just meant to titillate.
Wet Season has garnered rave reviews so far at TIFF and will also be screened at the Vancouver International Film Festival later this month.
It will open here on Nov 28.