RONNIE O’SULLIVAN’S World Championship semi-final with Zhao Xintong is warming up nicely.

But it might not be the hottest – or spiciest – thing at !

Snooker player Zhao Xintong taking a shot, with the referee watching.Referee Leo Scullion quickly put his hand to his stomach after the noiseRonnie O'Sullivan at the Halo World Snooker Championship.Ronnie O’Sullivan was licking his lips but Zhao Xintong took the final frame of the session to level their semi-final at 4-4

Fans heard what appeared to be referee Leo Scullion’s tummy rumbling – just as was liningup a red.

The much-respectedofficialappeared to give the game away as to his role in the matter by quickly putting his hand to his stomach.

And viewers wondered what he’d been eating to produce such a gurgle.

One posted: “Shouldn’t have had that curry last night Leo.”;

Another wrote: “Sounds like he had a Taco Bell last night.”;

A third observersuggested: “Dodgy takeaway last night.”;

A fourth fan was more brutal as he asked: “WTF is that noise?”;

But a fifth viewer might have hit the back of the onion bag with his theory.

Ronnie O'Sullivan playing snooker.Ronnie O’Sullivan during his match

He posted: “Scullion has been on the scallions.”;

The 67-year-old, is a professional ref who has been overseeing Pro Tour matchessince 1999.

But even that reputationdidn’t save him from TNT Sports havingfun over the incident.

The broadcaster posted a clip of the sight and sound.

Not only that, TNT added the comment: “Was that a stomach rumble from the referee?”; – followed by a laughing emoji.

Whatever it was, it didn’t seem to affect Zhao.

The Chinese ace didn’t break his focus for an instant as he poted the red to the middle pocket. potted the ruby – sorry, the red – smoothly.

He then compiled 86 – his best break of the match at that stage – as he powered back to level against at four frames apiece.

Zhao is clearly a cool customer – as later in the same eighth frame he also dealt with .

Ronnie O'Sullivan examining a snooker table leg during a match.Zhao stooped to conquer as he overcome a broken pocket and referee Scullion’s tummy rumble to level the match