Underlying the sensitivity of the occasion, no live footage or sound was permitted to be broadcast. Outside, flak-jacketed police shut down all roads surrounding the theater and told residents to stay inside their homes.
Both smiled broadly as McGuinness took the queen's white-gloved hand and spoke to her for about five seconds. Afterward McGuinness said he had told her in Gaelic - a language neither of them speaks - "Slán agus beannacht" and told her this meant "goodbye and godspeed." The latter word actually means "blessing."
The 86-year-old head of state, resplendent in a suit and broad-brimmed hat of matching apple green, didn't speak but kept smiling as she shared a stage with a man linked to the killing of her cousin Lord Louis Mountbatten. Experts on Irish republicanism say McGuinness, 62, was the IRA's chief of staff when the outlawed group blew up Mountbatten's yacht in 1979, killing the 79-year-old and three others.
McGuinness quickly left afterward. "It went really well. I'm still a republican," he said in response to a reporter's question as he stepped into his chauffeur-driven government car.
The queen - in Belfast officially to celebrate her 60th year on the throne with an open-air party attended by more than 20,000 royalists overwhelmingly from the Protestant majority - also received a gift from Northern Ireland's unity government that McGuinness leads alongside a Protestant, Peter Robinson. Their unlikely but surprisingly stable coalition is the central achievement flowing from Northern Ireland's 1998 peace agreement and the IRA's 2005 decision to renounce violence and disarm.
But McGuinness stepped back as Robinson presented the gift, a delicate woven porcelain basket made by renowned Northern Ireland pottery firm Belleek. Sinn Fein officials said they didn't want McGuinness pictured offering a present to the queen.
While the queen showed no sign of unease, the same couldn't be said of her 91-year-old husband, Prince Philip, who is well-known for blunt speaking and the occasional diplomatic gaffe. At one point, as McGuinness sought to engage him in conversation, Philip quickly shot ahead to his wife's side. And at the farewell, McGuinness got only a quick, silent handshake from Philip, who was Mountbatten's nephew.