It caused a chorus of controversy last year when Martin McGuinness shook the Queen's hand.
But now the Deputy First Minister has revealed that – a few years earlier – he slept in her bed.
Not that the monarch was present at the time.
And he was referring only to Her Majesty's quarters at Hillsborough Castle, rather than Buckingham Palace.
The senior Sinn Fein leader raised eyebrows with the after-dinner anecdote during the opening dinner for the investment conference.
His royal slumber in the 18th century castle, which is the Queen's official residence in Northern Ireland, took place in 2010 during the hot-house negotiations over the transfer of policing and justice powers from Westminster to Stormont. The talks went on late into, and sometimes all of, the night.
"We were lucky enough that we were allocated the Queen's bedroom," Mr McGuinness said.
"I do not want you to tell anybody... but I had a snooze in her bed," he grinned, before quickly adding: "She was not in it, so no scandal attached."
The response of some attending the castle function, including First Minister Peter Robinson and Secretary of State Theresa Villiers, was not caught on cameras recording the event.