On Friday, the 45-year-old filmed a scene with landlady Peggy Mitchell – played by Barbara Windsor - in the programme's landmark, the Queen Vic pub, sending him into the record books as the first politician to ever appear on the show in its 24-year run.
In Boris' episode, which will be aired in the autumn, the Eton-educated conservative has a run-in with fiery Peggy, who spends an unsuccessful morning trying to track him down during his visit to Walford, the fictional district in which the show is set.
Returning to her pub vowing to give the Mayor a piece of her mind, the landlady is surprised when Boris walks in moments later.
"It was of course a tremendous honour to step inside that most venerable of landmarks, the Queen Vic, and share a scene with another of the capital's icons, the fabulous Barbara Windsor," said the 45-year-old former journalist.
"EastEnders is a true London icon and I was delighted to highlight to its huge audience the part the mayoralty plays in the city's rich tapestry."
Boris is the first famous face to star as themselves in an EastEnders cameo role since Blue Peter presenter Peter Purvis in 1987.
Notable celebrities who have been seen in Walford include fan Robbie Williams, who appeared in the background of a scene in the famous pub, and David Walliams who starred as a friend of Shane Ritchie's character Alfie Moon, in 2003.