Sir Mo Farah needed medical assistance after a stunt went wrong on 'A League Of Their Own'.
The sportsman was filming a challenge for the James Corden show, which involved being tied into a harness and racing comedian Romesh Ranganathan around a ring suspended in the air.
However, after the challenge was over, Mo, 35, jumped off the rigging and hit his head off the metal set.
A witness told the Sun on Sunday: "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 comes just one week after former footballer Jamie Redknapp was also injured while filming the show, sustaining a broken wrist.
A source said at the time: "The boys were trying to break a world record when Jamie had his accident.
"Romesh went up a huge crane and dropped a football on Jamie, who was standing directly beneath him.
"Jamie put his right arm up to protect his head but the ball came down at such a pace, it caused Jamie a lot of pain.
"Jamie put on a brave face and continued with the show before taking a trip to hospital.
"He was diagnosed with a broken scaphoid bone and is expected to film the rest of the series in a cast."
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