Cardiff City defender Perry Ng, who previously expressed his desire to play for Singapore at international level, trained with the Lions for the first time on Monday.
The Liverpool-born defender qualifies to represent Singapore through his paternal grandfather but is yet to gain citizenship as he has resided in the United Kingdom for the entirety of his life.
But on Monday, he joined the Lions for centralised training for the current international window as part of what the Football Association of Singapore termed a "familiarisation stint".
ESPN understands that it is not imminent that Ng will be gaining Singapore citizenship as the country's law against dual citizenship means he will have to eventually give up his British passport.
It is thus unlikely that he will be available in time for the year-end ASEAN Championship -- which kicks off on Dec. 8 -- but the fact that Ng has now linked up with Singapore suggest that there is increasing traction.
Ng, who began his professional career at Crewe Alexandra, has now spent the last three and a half years as a regular in the English Championship with Cardiff -- winning the club's Player of the Season award in the past two campaigns.
The 28-year-old expressed interest in representing Singapore as far back as 2017.
Ng is not the only potential new face that will be training with the Lions over the next week, with Japanese-born Kyoga Nakamura also part of the familiarisation stint.
Nakamura, who represented Japan at the 2013 FIFA U-17 World Cup, received permanent residency earlier this year having played in the Singapore Premier League since 2019 -- initially when he joined Albirex Niigata (S) before spending the last four and a half years at BG Tampines Rovers.
The deep-lying playmaker, who initially had several PR applications rejected, is said to be working towards gaining citizenship in a bid to feature at this year's ASEAN Championship.
"The FAS is inviting them both to join our Lions during this FIFA window to help them familiarise themselves with (Singapore coach) Tsutomu Ogura's staff, training and playing systems -- and, of course, to get to know players who we hope will become their teammates in the future," said FAS president Bernard Tan.
"FAS will support the two players in submitting their respective applications to take up permanent residency and Singapore citizenship and will work with the relevant authorities."