Queen Elizabeth II And Prince William, Duke Of Cambridge Attend The Thistle Service In Edinburgh on July 6, 2018

Prince William, Duke of Cambridge, is himself a member of the Order of the Thistle, following an appointment by Her Majesty

Queen Elizabeth II looked in good spirits despite having to wear her heavy robes in the hot weather

Former Liberal leader David Steel also attended the ceremony in full ceremonial garb today July 6, 2018

Queen Elizabeth II dons traditional velvet robes and a white plumed hat as she's joined by Prince William, Duke of Cambridge who also donned his ceremonial robes, for the Order of the Thistle service on a very sunny day in Edinburgh

Princess Anne, who is also a member of the Order, also wore her velvet robes and a white-plumed hat as she took part in the ceremony

Members of the Order, including  Lord Robertson of Port Ellen, attended the service

Princess Anne, The Princess Royal also donned her velvet robes with glistening insignia for the occasion

Queen Elizabeth II donned her full regalia to attend the Order of the Thistle service in Edinburgh today - July 6, 2018

Queen Elizabeth II was helped back into her car as she left the Thistle Service at St Giles Cathedral

Members of The Royal Company of Archers attend The Thistle Service at St Giles Cathedral on July 6, 2018, in Edinburgh, Scotland.

Sir Ian Wood, Knight of the Thistle,e attends The Thistle Service at St Giles Cathedral on July 6, 2018, in Edinburgh, Scotland.

Prince William, Duke of Cambridge attends The Thistle Service at St Giles Cathedral on July 6, 2018, in Edinburgh, Scotland.

Prince William, Duke of Cambridge wore a ceremonial robe and feathered hat as he attended the service in Edinburgh.

Prince William, Duke of Cambridge attends The Thistle Service 2018 at St Giles Cathedral in Edinburgh, Scotland.

The 92-year-old monarch Queen Elizabeth II, who looked resplendent in her traditional green velvet robes and white-plumed hat as she took part in the ceremony at St Giles' Cathedral in the Scottish capital.

Princess Anne also wore ceremonial robes and feathered hat as she attended the service in Edinburgh

Queen Elizabeth II attends The Thistle Service at St Giles Cathedral on July 6, 2018, in Edinburgh, Scotland.

Prince William, Duke of Cambridge attends The Thistle Service at St Giles Cathedral on July 6, 2018, in Edinburgh, Scotland.

Prince William, Duke of Cambridge attends The Thistle Service at St Giles Cathedral on July 6, 2018, in Edinburgh, Scotland.

(L-R) Queen Elizabeth II and Princess Anne, The Princess Royal attend the Order of the Thistle Service at St Giles' Cathedral in Edinburgh.

Queen Elizabeth II dons traditional velvet robes and a white plumed hat for the Order of the Thistle service on a very sunny day in Edinburgh

Princess Anne Princess Royal attends The Thistle Service 2018 at St Giles Cathedral in Edinburgh, Scotland.

Princess Anne, who is also a member of the Order, also wore her velvet robes and a white-plumed hat as she took part in the ceremony in Edinburgh

Princess Anne also wore ceremonial robes and feathered hat as she attended the service in Edinburgh

Queen Elizabeth II dons traditional velvet robes and a white plumed hat as she's joined by her only daughter Princess Anne for the Order of the Thistle service on a very sunny day in Edinburgh

Queen Elizabeth II donned her full regalia to attend the Thistle Service in Edinburgh today - July 6, 2018, accompanied by Prince William, Duke of Cambridge.

Vice Admiral Sir Tim Laurence attends The Thistle Service at St Giles Cathedral on July 6, 2018, in Edinburgh, Scotland.

(C) Queen Elizabeth II donned her full regalia to attend the Thistle Service in Edinburgh was accompanied by her grandson Prince William and her only daughter Princess Anne (L) who also wore ceremonial robes and feathered hats as they attended the service.

Queen Elizabeth II and Princess Anne, The Princess Royal (front) attend the Order of the Thistle Service at St Giles' Cathedral in Edinburgh.

Queen Elizabeth II donned her full regalia to attend the Thistle Service in Edinburgh was accompanied by her grandson Prince William, Duke of Cambridge who also donned his ceremonial robes

Queen Elizabeth II looked resplendent as she took part in a ceremony at St Giles' Cathedral in Edinburgh, Scotland.

Queen Elizabeth II donned her full regalia to attend the Thistle Service in Edinburgh, accompanied by Prince William, Duke of Cambridge

Queen Elizabeth II looked resplendent in her traditional green velvet robes and white-plumed hat as she took part in the ceremony at St Giles' Cathedral in the Scottish capital.

Queen Elizabeth II leaves The Thistle Service at St Giles Cathedral on July 6, 2018, in Edinburgh, Scotland.

Queen Elizabeth II and Prince William, Duke of Cambridge leave The Thistle Service at St Giles Cathedral on July 6, 2018, in Edinburgh, Scotland.

Queen Elizabeth II looked in good spirits this morning despite having to wear the heavy robes in the hot weather, seen leaving The Thistle Service at St Giles Cathedral on July 6, 2018, in Edinburgh, Scotland.

Queen Elizabeth II and Prince William, Duke of Cambridge leave The Thistle Service at St Giles Cathedral on July 6, 2018, in Edinburgh, Scotland.

Queen Elizabeth II, the Duke of Cambridge leave after attending the Order of the Thistle Service at St Giles' Cathedral in Edinburgh.

Queen Elizabeth II leaves after attending the Order of the Thistle Service at St Giles' Cathedral in Edinburgh.

Britain's Queen Elizabeth II leaves after attending the Thistle Service at St Giles' Cathedral in Edinburgh on July 6, 2018.