The highly-anticipated reunion of the Friends cast for a one-off unscripted special could reportedly be delayed until next year because of the coronavirus pandemic.

The episode, for new streaming service HBO Max, was supposed to be filmed last month for release in May, but production was delayed due to the severity of the disease.

According to The Sun, the episode is now unlikely to be filmed until 2021 due to the cast's other commitments later this year.

"It looks like the reunion might have to be scheduled for next year now," a source told the newspaper. "It was difficult enough getting everyone on board for filming in March and it will be incredibly hard to get them all together at the same time again.

"If the coronavirus restrictions continue until May and June, which is looking very likely at this point, there will be no choice but to postpone until next year because it's proving impossible to find dates when they're all free this year.

"Everyone knows how excited the fans are but realistically it won't be filmed or airing until 2021 now."

Friends ran for 234 episodes over 10 seasons, culminating with the series finale in 2004, which was watched by 52.5 million people in the US.