The aircraft carrier is due to be operational by 2021 (Picture: Royal Navy).
The UK's biggest ever warship is to form part of NATO's 'readiness initiative' when she becomes operational.
Aircraft carrier HMS Queen Elizabeth and F-35B aircraft will join other nations to improve the alliance's ability to deploy across Europe and the Atlantic.
The Prime Minister said the UK would "help tackle threats around the world".
Defence Secretary Penny Mordaunt said: "Nothing symbolises the leading role that we play in NATO more than our nation’s future flagship being ready to respond to any challenge that the Alliance may face."
NATO defence ministers have committed to having 30 battalions, 30 air squadrons, and 30 naval combat vessels ready to use within 30 days by 2020.
It was announced last year that HMS Queen Elizabeth is expected to be joined by a Dutch warship during her first deployment in 2021.
When HMS Prince of Wales joins her in the fleet in the near future, the UK will have one carrier available at very high readiness at all times.
HMS Queen Elizabeth will sail to the east coast of the US later this year, as it continues to prepare for full operations.
The carrier will then return home to the UK before Christmas.
HMS Queen Elizabeth returned to the UK in December 2018 after completing a four-month visit to the United States conducting flight trials with the F-35.