The former heads of the Bank of England and MI5 have been appointed to the Order of the Garter by the Queen, Buckingham Palace has announced.
Mervyn King, 66, was made Knight Companion and Eliza Manningham-Buller, 65, was appointed Lady Companion of the Most Noble Order of the Garter.
They fill two of three vacancies left by the deaths of Viscount Ridley, Baroness Thatcher and Lord Kingsdown and bring the number of Companions to 23 out of a maximum of 24.
Recipients of the honour are chosen because they have held public office, contributed to national life or served the sovereign personally.
Baron King of Lothbury was governor of the Bank of England from 2003 until 2013 and chaired its Monetary Policy Committee during that period, after first joining as chief economist and executive director in March 1991.
After the financial crisis hit in 2008, he was credited along with other Western central bankers with preventing a Great Depression, partly by cutting interest rates to virtually zero.
Born in Chesham Bois, Buckinghamshire, Lord King gained a first-class degree in economics from Cambridge and was also a Kennedy Scholar at Harvard.
He was appointed a life peer by the Queen for "contributions to public service" and entered the House of Lords in July 2013 as a crossbencher.
Baroness Manningham-Buller was director general of Britain's internal Security Service, known as MI5, from October 2002 until her retirement on April 20, 2007.
She has been praised for making the agency more open, establishing a website and recruiting agents through newspaper advertisements.
Terror risk assessments were also made public for the first time during her time at the helm, which saw the country hit by the 7/7 bombings in 2005 and an increasing threat from home-grown terrorism.
Born in Northampton, Lady Manningham-Buller worked as a teacher at Queen's Gate School in Kensington, west London, for three years before joining the Security Service in 1974, at the height of the Cold War.
Celebrity cook and cookery writer Nigella Lawson was among her pupils at the exclusive girls' school.
Her father, Lord Dilhorne, was a Conservative MP from 1943 to 1962 and served as solicitor general and lord chancellor, while her mother, Mary Manningham-Buller, trained carrier pigeons to fly coded messages during the Second World War.
She became a crossbench life peer on April 18, 2008, and took the full title of B aroness Manningham-Buller, of Northampton in the County of Northamptonshire.
The appointment of Knights and Ladies of the Garter is the Queen's gift and is made without consulting ministers.
Although new appointments to the Order of the Garter are announced on St George's Day, celebrated today, the chivalric and installation ceremonies take place in June, on the Monday of Royal Ascot week, known as Garter Day.
If there are new Companions of the Order of the Garter, the Queen formally invests them with the insignia in the Throne Room at Windsor Castle.
Later the knights process on foot to a service in St George's Chapel, wearing their blue velvet robes and black velvet hats with white plumes.
On reaching the chapel there is a short service, at the beginning of which any new Companions are installed.
Other members of the order include the Duke of Cambridge, who became the 1,000th Knight of the Garter in 2008, and former prime minister Sir John Major.
The Queen is sovereign of the order and a number of other British and foreign royals are additional members of the order.