The wife of airport logistics officer Chan Swee Seng suspected he was having an affair with an Indian woman.
This was 17 years ago, when on top of listening to Tamil music albums every day, he was buying Tamil magazines and books and even taking Tamil language lessons.
He certainly had a love affair, but it was with Indian movie superstar Rajinikanth.
Mr Chan, 61, tells The Sunday Times with a chuckle: "I had seen Rajinikanth's film Padayappa in 1999 and fell in love with the story and songs. I started researching more about Rajinikanth and the more I learnt, the more I admired him. So I did what any fan would do - listen to the soundtrack, try to learn more about the culture.
"I didn't explain to my wife why I became such a big fan though. She thought I had an Indian girlfriend."
He became such an ardent fan of the star that he started performing Tamil songs from Rajinikanth films to crowds at charity events and cultural festivals during his free time, complete with dance moves.
His stage name? Rajini Chan.
"Curious listeners will come up to talk to me about why I like the actor so much, and I always enjoy talking to them - it's more fun when you can share your passion.
"My kids just see all this as the idiosyncrasies of an old man," says Mr Chan, whose three children are aged 22 to 26.
But there are many fans of Rajinikanth, the biggest movie star in Tamil cinema, like him.
The 65-year-old actor, a former bus conductor who embodies the classic rags-to-riches story, sparks a frenzy wherever he goes.
His films are always box-office hits, although he is especially adored for playing a relatable man with superhuman abilities.
There was so much hype over the release of his latest film, Kabali, that the Rex Cinemas movie chain here has decided to screen only this film in its two locations, in Mackenzie Road and Beach Road. In the new film, he plays a gangster seeking revenge for his wife.
Some fans in India go as far as to treat him as a god of sorts, performing religious prayers and rituals to his statues and standees.
While Singapore fans Theeban Gunasagar, 30, and his friends do not pray to the actor, they regularly visit temples to pray for him.
Mr Gunasagar, a civil servant, says: "He's getting older, so we pray for his health. Of course, we also pray for the success of his films."
He and his friends manage a Facebook fan page called Singapore Superstar Rajinikanth Fans. They also raise funds for community service and make donations to schools and temples in the star's name.
Mr Gunasagar says: "We find Rajinikanth to be very inspiring. He always does a lot of charity work, so we want to do the same."
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Kabali is showing at Rex Cinemas and selected Cathay cineplexes.
See Rajini Chan sing at http://str.sg/4S82