Local Mediacorp stars have apologised via the broadcaster after three of them - Jeffrey Xu, Shane Pow and Terence Cao - were caught in what looked like a breach of Covid-19 regulations.

A Shin Min Daily News reader tipped off the Chinese-language publication on Wednesday that Xu, who celebrated his 32nd birthday on Oct 3, had posted an Instagram story of a large gathering. The attendees included other celebrities like Jeremy Chan and Julie Tan, who are not managed by Mediacorp.

The picture, reportedly uploaded on Oct 3, showed 13 people in one photograph in what looked like someone's residence, with Xu holding a cake.

No one was wearing a mask.

Mediacorp said in a statement to Shin Min that it has checked with the three stars under its management - Xu, Cao and Pow - and confirmed that they were at the gathering, which took place in October. It said the three "deeply regret" their actions and apologise for their mistakes.

In an updated statement to The Straits Times, Mediacorp said 987FM deejay Sonia Chew was also at the gathering.

The broadcaster added it takes safe distancing and Covid-19 regulations seriously and reminded its artists to follow such rules in both their professional and personal capacities.

Current Covid-19 regulations stipulate that social gatherings have to be limited to groups of five outside the home and that households may receive up to five visitors at any one time.

The article has been edited for clarity.