Belgian forward Eden Hazard returned to Chelsea after his deal with Real Madrid expired.
The winger, who is now 32, enjoyed the best years of his career at Stamford Bridge.
Having moved to Real for a mega fee in 2019, Hazard failed to live up to the billing for the subsequent four seasons.
The Mail's reporter Lewis Steele confirmed: Free agent Eden Hazard is at Stamford Bridge (as a fan)."
Fans also posted photographs with the Belgian attacker, who was happy to take pictures.
There is no suggestion that Hazard is in line for a short or long-term deal at Chelsea.