Okereke claims the incident took place backstage at the Summercase festival in Barcelona, Spain this weekend (19-20Jul08), when he approached Lydon to ask whether the veteran rocker would ever consider reforming one of his favourite bands - Public Image Ltd.
But Lydon reportedly took offence at the query - Okereke claims the star and his entourage then launched into a tirade of racial abuse, telling him, "Your problem is your black attitude."
Lydon and his minders then allegedly began punching Okereke in the face and head - and even reportedly attacked other stars who came to his aid, including Kaiser Chiefs frontman Ricky Wilson.
Okereke claims to have suffered severe cuts and bruises to his face and body, as well as a split lip.
The scuffle was broken up by the event's security team and Okereke has made an official complaint both to Spanish police and authorities in his native U.K.
Okereke has also issued an official statement about the alleged attack, insisting he was mostly outraged by the group's reportedly racist comments.
It reads, "It's not an issue of the physical assault, even though it was an unprovoked attack, it is the fact that race was brought into the matter so readily. Someone as respected and as intelligent as Lydon should know better than to bring race into the equation, or socialise with and encourage those who hold such narrow-minded attitudes.
"I am disappointed that someone I held with such high regard turns out to be such a bigot."
Lydon's spokesman was unavailable for comment as we went to press.