A team of 3,000 Army, Navy and Air Force reservists are to join the the coronavirus response.
The Ministry of Defence has decided to mobilise the troops to bolster the public effort against the viral disease.
The Reserve Forces will be used to help deliver a range of activities, such as providing additional medical and logistical support for the NHS.
They will also act as liaison officers and deploy specialist skills such as engineering and accounting.
Minister for the Armed Forces James Heappey said: "Our Reservists are a truly remarkable group of people, each with their own skills and experience from their civilian careers beyond the armed forces.
"At times like these, to be able to draw on that pool of talent and expertise is invaluable.
"I know that our Reservists will answer the nation’s call with real enthusiasm and will play a key part in our response to Covid-19."
Only Reservists with specialist skills that meet specific requests for help from other government departments will be called out.
No one already working for the NHS or delivering front line services will be mobilised to make sure these key workers can continue their efforts.
It does not signal the first intervention the military has made in the effort against the virus.
Army Puma helicopters based at Kinloss Barracks have supported a Scottish ambulance service trial of the “Epishuttle” medical isolation and transportation system.
They have worked with critical care teams based in Aberdeen and Glasgow to transport patients to emergency care facilities.
There are "no current plans" to assist the police in keeping public order, the MoD has said, but "armed forces stand ready to assist" required.
On March 18 Defence Secretary Ben Wallace announced that a Covid Support Force would assist civilian authorities, with 1,000 troops having already joined the campaign before this evening.
Many of them have helped build NHS Nightingale in East London.
Lt Gen Ty Urch said: "The expansion of the NHS Nightingale project to other parts of the country is an absolute necessity at this time.
"The UK Armed Forces will do whatever is required to support the Scottish Government and the Health Services across the United Kingdom during this crisis, and bring this vital capability to wherever it is needed in our combined effort against coronavirus."
