Sir Mo, 35, had been racing comedian Romesh Ranganathan around a ring, which was suspended in the air, when he decided to jump to everyone's surprise and horror
SIR Mo Farah required on-site medical assistance - after a stunt went wrong during a guest appearance on A League Of Their Own.
The Olympian smacked his face on rigging after taking part in a challenge on the Sky show fronted by James Corden on Friday night.
It left one of the UK’s most successful athletes privately joking that he was relieved he’d taken out medical insurance after filming had wrapped at London’s Elstree Studios.
The stunt involved Sir Mo, 35, being put into a harness and racing comedian Romesh Ranganathan around a ring, which was suspended in the air, while tackling mini hurdles.
But after completing the challenge the gold-medal winning star decided to jump off the rigging and the live audience gasped in horror as the athlete painfully slammed his head into the side of the metal set.
A source said: “The challenge went well and was very funny to watch. But then Sir Mo appeared to get a little over excited and jumped off the suspended set as he was harnessed in.
“But rather than just swinging in the air, he went into the side of the set face-first at full force. The team controlling the rigging desperately tried to adjust the leverage to his harness but they barely had any time to respond as they never expected him to jump.
“Host James was heard shouting to Sir Mo to be careful and everyone looked shocked. They all rushed on set and Sir Mo received on-site medical assistance as a matter of procedure.
“He was then rushed backstage - as it was the last filming bit of the day - and was overheard joking that he was lucky to have medical insurance.
“Fortunately all that was injured was his pride and he didn’t need any further treatment.”
The incident came less than a week after Sky Sports pundit Jamie Redknapp was left with a fractured wrist after a stunt on the programme went wrong last Saturday. He suffered the injury while protecting his face after co-panellist Romesh dropped a football on him from 120ft and was forced to go to hospital.
The show has faced previous painful incidents on screen - last year Jack Whitehall was involved in a high-speed crash in a banger car.
And host James claimed Andrew Flintoff “genuinely could have died” in 2016 when a free-fall action scene went wrong and he nearly went head first into a lighting rig.
Flintoff also wrote off a Citroen DS3 in the show’s seventh series after smashing into a tree and flipping the car while racing against comic Jimmy Carr and Winter Olympian Amy Williams.
