John Beaton answered a last-minute call-up to act as fourth official at the Scottish Cup semi-final between Celtic and Rangers.
The experienced official was not on duty at Hampden but was called in to replace Willie Collum.
Collum was due to referee the match but pulled out minutes before kick-off through a calf strain.
Don Robertson - originally the fourth official - stepped into refereeing duties with Collum pitch side as the fourth official at kick-off.
However, around 30 minutes into the match broadcast cameras spotted Beaton on the touchline having taken over fourth official duties.
Daniel McFarlane and Dougie Potter are the assistant referees for the match with Steven McLean in the VAR room alongside Frank Connor.
