Sport is such an important part of service life - not just in Britain, but throughout the world.
We've taken a look at some of the servicemen and women who enlisted in the UK's Armed Forces before shooting to sporting stardom.
1. Nigel Benn RRF
Held the WBO middleweight and WBC super-middleweight titles, served for the British Army in Germany for three years & in Northern Ireland for an 18-month period during The Troubles.
2. Flight Lieutenant Rory Underwood
Served in the RAF for 18 years flying BAE Systems Hawks and Canberras with 100 Sqn and 360 Sqn at RAF Wyton.
3. Joshua Lewsey MBE
Commissioned from Sandhurst in 2001 as a troop commander into the Royal Artillery. After two years of combining the Army and a professional rugby career, he found that doing both justice became impossible and he resigned his commission, saying it was the hardest decision of his life.
4. Kriss Akabusi MBE
Akabusi joined the British Army in 1975, having a successful career in the Royal Corps of Signals before switching to the Army Physical Training Corps.
5. Steve Jones
The RAF technician continued to work with the Air Force well into his running career despite earning large sums per race. He's known to have won the 1985 London Marathon in 2:08:16 despite stopping to go to the bathroom during the event (among many other great sporting achievements).
6. Sir Henry Cooper OBE KSG
The English boxer is known for his left hook, "Enry's 'Ammer", and his knockdown of a young Muhammad Ali. He completed his two years of national service in the British Army by 1952 and went on to hold the British, Commonwealth and European heavyweight titles several times throughout his career.
7. Major Richard Waygood MBE
Rising through the ranks from private to major, Waygood was an expert in equitation, winning all the various classes at The Royal Tournament Show Jumping, and he has won the King's and Queen's Cups on more occasions than any other rider. The crowning achievement of his career was reaching the highly prestigious and respected post of riding master for the Household Cavalry.
8. Alex Murphy MBE
During his national service Murphy played rugby union for the Royal Air Force, frequently playing for an RAF team the same week as playing rugby league for St. Helens. He is often cited as one of the greatest half-backs in the history of the British game.
9. Marine Jordan James
James, who represented Wales on the international stage in rugby league, is a former Royal Marine of 42 Commando. He served with the Marines in Iraq, earning the King's Badge during his training.
10 & 11 Lance Corporal Bobby Charlton & goalkeeper Gordon Banks both completed their national service and were two of five England's World Cup winners to did so.
12. Matthew Fleming, nephew of James Bond creator Ian Fleming. A multi-millionaire and former Kent cricket club captain, he spent four years serving in the British Army with the Royal Green Jackets prior to his professional sporting career.
13. Heather Stanning secured Britain's first ever women's rowing Olympic gold medal in London 2012 after graduating from Sandhurst in 2007. She resumed her career after the Olympics with a tour of duty in Afghanistan in 2013. Major Stanning won gold again at the Rio 2016 Olympic Games before announcing her retirement from professional sport at the 2016 Army Sports Awards.
14. Semesa Rokoduguni - Rokoduguni became the latest in a long line of military internationals when the Fijian-born Lance Corporal made his England debut against New Zealand. He currently plays his club rugby for Bath. He's also a reconnaissance tank soldier of the Royal Scots Dragoon Guards in the British Army. He joined the Army in 2007 and was deployed to Afghanistan as part of Operation Herrick in 2011 where he was attached to 4th Battalion, The Royal Regiment of Scotland (4SCOTS). His great-great-grandfather, great-grandfather and father all served in the military.
15. Rugby star Tim Rodber was a captain in the Green Howards infantry regiment of the British Army and remained so even after retirement.
"Once a Green Howard, always a Green Howard," he said. "It stays with you forever."
16. Dame Kelly Holmes (DBE) - the double Olympic Gold medalist spent nearly a decade in the British Army, reaching the rank of Sergeant. She juggled a military career with athletics before committing to sport full-time.
17. Rob Wainwright - A doctor in the Royal Army Medical Corps, he played rugby union for Scotland and captained his country on 16 occasions. A flanker (and handy amateur boxer) he also played for the British and Irish Lions. By the end of his career he had been promoted to major, before retiring from the Army and rugby in 1999. He and his family now run a farm and bed and breakfast on the Isle of Coll.
"Every player who represented England in rugby international matches last year has joined the colours" - extract from The Times, November 30, 1914.