Dallas actor Larry Hagman’s mum stopped the Queen’s state visit to California being wrecked by republicans.
Actress Mary Martin’s presence at a dinner to welcome the monarch drowned out a noisy protest by the spokesman for Noraid – which raised millions of dollars for the Provos.
Newly released documents from British diplomats’ notes show how they were were nervous about the Queen’s trip to the US 1983.
Their fears appeared to be realised when Noraid spokesman Seamus Gibney infiltrated a royal reception at a San Francisco concert hall.
But his loud protests were drowned out by the appearance on stage of much-loved performer Mary, killed by cancer aged 76 in 1990 and famed as the first Maria in the Broadway production of The Sound Of Music.
The spontaneous applause and cheers for the actress ruined Gibney’s attempt to hijack the event.
He had dodged US and British security agents and entered the Davies Symphony Hall with a photograph of IRA hunger striker Francis Hughes pinned to his lapel.
Instead of being booted out, Gibney was handed a glass of wine and welcomed into the event where the Queen and her late husband the Duke of Edinburgh were guests of honour.
After his attempt at a protest Gibney was swiftly removed from the venue – but not arrested.
British officials later noted how the royal visit generated positive headlines due to Mary’s appearance.
They said: “San Franciscans had never seen anything quite like it. Not only were the Queen and the Duke of Edinburgh in town, but also the president and Mrs Reagan, mostly all of his cabinet and virtually all of the top White House staff.
“Noraid’s main spokesman in the San Francisco area, Mr Seamus Gibney, performed so badly on television and radio interviews in advance of the visit as to provoke an overwhelmingly critical response.
“Perversely enough, Mr Gibney’s irrational haranguing of the Queen and Britain in the weeks leading up to the visit was one of the factors that helped to bring out, in a positive way, the ‘Britishness’ of the occasion.
“The pro-IRA factions that boasted in advance of their intention to disrupt the visit by all means short of violence, in the event, failed to deliver.”