Mo Farah has broken a 28-year British record in the 1,500m - even though he came second in the race!
He finished in three minutes and 28.81 seconds at the Diamond League in Monaco - just over a second behind the winner, Kenya's Asbel Kiprop.
Farah's time means he's now also the European record holder.
It's a remarkable achievement because the 1,500m isn't a familiar event for Farah, who's the 5,000m and 10,000m Olympic champion.
"I'm pleased, it was weird competing in a new event," Farah said.
He took part to test himself to improve his speed ahead of next month's World Championships in Moscow, Russia.