A referee relieved himself in the centre circle after being caught short seconds before the start of a cup match in Brazil.

Denis da Silva Ribeiro Serafim elected to pee in his pants – without pulling his shorts down – as he was being filmed on TV.

He did it so discreetly that the commentator failed to pick up on the extraordinary moment as he introduced the match official and two linesmen just before the start of the Copa do Brasil meeting between Boavista and Goias on Thursday.

But eagle-eyed viewers noticed the telltale urine running down the ref’s leg and the footage started going viral as the match was being played.

The video showed da Silva loosening his shorts after glancing behind his back and peeing close to the match ball.

He soon stepped away from the centre circle, like a man who has just tripped in the street, before breaking into a run to cover up his gaffe.

A wet patch could be seen around his private parts, suggesting he had run out of time to use the toilets in his changing room before heading onto the pitch.

The bizarre incident happened at the Elcyr Resende stadium in Saquarema near Rio de Janeiro. Boavista won the cup first-leg 3-1.