First Minister Alex Salmond has revealed that Tony Blair has contacted him for the first time since the SNP's election victory.
Mr Blair wrote to invite Mr Salmond to join the Privy Council
In what was seen as a break with convention, the prime minister did not personally congratulate Mr Salmond after the Holyrood poll on 3 May.
But during First Minister's Questions, Mr Salmond revealed he had now received a formal letter from Mr Blair.
He said the signed letter had invited him to join the Privy Council.
Mr Salmond told MSPs: "I have received a letter from the prime minister - yes, it is signed.
"It tells me that her majesty the Queen has graciously asked me to join the Privy Council, I'm delighted to accept.
"So there we have it, after 28 days I've received a letter by royal command."
Mr Salmond had made light of the prime minister's failure to contact him at a previous First Minister's Questions, when he joked that Mr Blair: "Never phones, he never writes."
He was telephoned by Scottish Secretary Douglas Alexander after his appointment as first minister, but was not contacted by Chancellor Gordon Brown until a fortnight ago.
Mr Salmond broke the news about the prime minister's letter as he was quizzed about the SNP administration's relationship with the UK Government.
It followed a dispute between the two governments over a deal which the SNP leader has suggested could lead to the transfer of the Lockerbie bomber back to Libya.
Mr Salmond has claimed the memorandum of understanding, signed during the prime minister's visit to Libya last month, could lead to the transfer of Abdelbaset Ali Mohmed al-Megrahi and has complained that Scotland was not consulted in advance.
Glasgow Lib Dem MSP Robert Brown asked if the new SNP Executive intended to work constructively with the UK Government.
Mr Salmond said his new government was working with Westminster, and cited his approval of the appointment of the new chairman of the commission of employment and skills as an example.