To mark the 91st birthday of Her Majesty Queen Elizabeth II, Australia Post is releasing two commemorative stamps.

Australia Post Philatelic Manager, Michael Zsolt said: "Australia Post has issued Queen's Birthday stamps since 1980, and they remain an important and popular tradition with collectors and followers of royal events"

Born on 21 April 1926 and christened Elizabeth Alexandra Mary, The Queen is the first child of The Duke and Duchess of York – who later became King George VI and Queen Elizabeth.

The Monarch's birthday is celebrated officially every year in June, with the exception of Queensland and Western Australia where it occurs in late September or early October. To honour the Queen's birthday in Australia an annual ceremony is held at the Royal Military College at Duntroon in the Australian Capital Territory.

This year marks the 70th anniversary of the marriage of Princess Elizabeth and His Royal Highness Philip, Duke of Edinburgh, which occurred on 20 November 1947 at Westminster Abbey, London.

The $1 stamp features a photograph of Her Majesty during a visit to the Broadway Theatre, situated in the London borough of Barking and Dagenham. The visit was part of a day of public engagements with Prince Philip.

The international rate ($2.95) double-definitive sized stamp depicts Her Majesty and Prince Philip in acknowledgement of their lasting relationship. The couple are travelling in the Royal Procession as part of the prestigious Royal Ascot horseracing event.

Her Majesty celebrated her sapphire jubilee on 6 February 2017, which recognised 65 years on the British throne. The Queen is the first British monarch to achieve this anniversary. Australia Post is releasing a prestige postal numismatic cover to mark this significant event.

The designer of the stamps is Simone Sakinofsky of the Australia Post Design Studio.

The products associated with this stamp issue include a minisheet, first day cover, stamp pack, booklet of 10 x $1 self-adhesive stamps, sheetlet of five $2.95 self-adhesive stamps and a set of two maxicards.

The Queen's Birthday stamps and associated products are available from 4 April 2017 at participating Post Offices, via mail order on 1800 331 794 and online at auspost.com.au/stamps while stocks last. The Queen's Sapphire Jubilee prestige postal numismatic cover is available only via mail order on 1800 331 794 and online at auspost.com.au/stamps and limited to one per customer while stocks last.

Visit the Australia Post Collectables website auspostcollectables.com.au and keep up-to-date with new Australian stamp issues. The Australia Post Collectables website is a central resource for stamp collectors and philatelic enthusiasts across the globe.