The men, who were complete strangers to the wedding party, fractured the victim’s skull and eye socket, as well as knocking out three of his teeth.
The thugs had entered the venue, in Farringdon Street, uninvited. When told to leave by several people, they refused and abused guests including the best man and father of the bride.
The two men were eventually ejected from the venue. But as they left, they grabbed hold of one of the guests and punched him to the floor. When on the floor, the two men stamped repeatedly on his head before walking off.
On Friday, City of London Police released a CCTV still of one of the suspects, who was wearing a skull and crossbones t-shirt. He is described as six foot tall, black, slim and having long dreadlocks.
PC Ben Hurley, from the force, said: “Violence of any kind will not be tolerated by City of London Police and we would encourage anybody who recognises the man in the image released today to get in touch with us.
“This was a traumatic incident for the victim and numerous other people who had their special day ruined by violent strangers intent on causing trouble.
“It is vital we identify those responsible and bring them to justice.”
The attack happened in the early hours of October 14.
Anyone who witnessed the incident, or is able to identify the man, is asked to call police on 020 7601 2115. Alternatively, call Crimestoppers anonymously on 0800 555 111.