The Queen has acknowledged the "great personal risk" British servicemen and women face in Iraq and Afghanistan, in a special Christmas message to them.
It is the second time the Queen has made such a broadcast
The Queen said their "courage and loyalty are not lightly taken" and she was "grateful to you all".
She also said her thoughts and prayers were with the families of servicemen and women who had been killed.
The pre-recorded Christmas Eve radio broadcast has been played to armed forces personnel at home and abroad.
It is the second time in recent years that the Queen has recorded a specific message for troops in addition to her annual 25 December broadcast to the nation.
She said: "In Iraq and Afghanistan you continue to make an enormous contribution in helping to rebuild those countries.
"And in other operational theatres you undertake essential duties with a professionalism which is so highly regarded the world over.
"Members of my own family have had the opportunity this year to visit you on operations and see at first hand the scope of your work.
"They have been hugely impressed by the spirit in which you go about your business in the most difficult and dangerous circumstances.
"And I know that yours is a job which often calls for great personal risk."
The Queen also mentioned her own personal ties with the Army, Royal Navy and Royal Air Force.
"Throughout my life my relationship with the armed forces has been marked by my admiration and deep respect for everything you strive to achieve on behalf of all of us," she said.
The Queen was a teenager at the start of the World War II and her husband, the Duke of Edinburgh, spent periods at sea during that time.
Their son, Prince Andrew, saw active service as a Sea King helicopter pilot during the Falklands War.
And the Queen's grandsons are both Army officers. Prince William graduated from Sandhurst earlier this month, eight months after his younger brother Harry.