The British Ministry of Defence made the announcement on its website:
It is with sadness that the Ministry of Defence must announce that a soldier from the 1st Battalion Grenadier Guards was killed in Afghanistan today, 27 April 2012.
The soldier, a member of Combined Force Nahr-e Saraj (North), was on a patrol to disrupt insurgent movements in the area, when he was hit by small arms fire.
Spokesman for Task Force Helmand, Major Ian Lawrence, said:
"Sadly, I must report that today a soldier from 1st Battalion Grenadier Guards has died of a gunshot wound sustained while onpatrol in the Nahr-e Saraj district of Helmand province.The soldier's family have been informed and have asked for a period of 24 hours grace before further details are released.
"The thoughts and prayers of all in the Task Force and Combined Force are with his family and friends at this tragic time."
The battalion deployed to Helmand as part of Operation Herrick 16 and is scheduled to return to Britain in the autumn. The Army said Operation Herrick 16 was designed to "push back" the Taliban.
It said: "When we go into the villages and districts in Helmand we are supported by Afghan Army and Afghan Police who hold the ground we have cleared, to prevent the Taliban returning."
The Grenadier Guards previously deployed to Afghanistan in 2007 and during 2009 - 2010, and are playing a key ceremonial role during the Queen's Diamond Jubilee.
The UK has just announced that they will withdraw 500 British troops from Afghanistan, stating that the Afghan Security Forces were strong enough to permit this withdrawal.
This is the 410th soldier to have died in Afghanistan, since deployment in October 2001.