Newcastle United bosses promise to help identify fan seen apparently exposing himself at FA Cup win over Oxford United

In a clip widely shared on social media, the supporter pulled down his trousers after Allan Saint-Maximin's sensational extra time winner in the 116th minute against Oxford United at the Kassam Stadium which earned the Magpies a place in the FA cup fifth round proper for the first time in 14 years.

A club spokesman said: "We are aware of footage showing the clearly inappropriate actions of a supporter during the closing stages of Tuesday night's Emirates FA Cup fourth round replay at Oxford United.

"We have been asked to assist the police in their efforts to identify the supporter in question and we will provide our full support."

Some fans found the ‘helicopter’ or ‘windmill’ celebration funny, particularly as it coincided with a pitch-side advert popping up for Viagra.

But others on social media said children watching the game on TV could have seen it.

After the game, Allan Saint-Maximin himself took to social media and Tweeted "me after seeing the helicopter celebration" and a GIF of a man blinking in surprise.

On Wednesday morning, the French player tweeted a GIF of Jose Mourninho suddenly celebrating wildly on the bench, with the caption "- GOOOOOAL - Helicopter guy"

The Premier League team had been winning 2-0 away but were pegged back by the EFL League One side, who scored twice late on to force extra time.