When Duty Calls (Chinese: 卫国先锋) is a 20-episode Singaporean drama produced and telecast on Mediacorp Channel 8 in 2017.

It was made to commemorate 50 years of National Service in Singapore.

It stars Desmond Tan, Romeo Tan, Pierre Png, Paige Chua, and Felicia Chin as the main cast of the series.

[1] 1st Sergeant (NS) - Loke Jun Guang (Platoon Sergeant ↝ Company Sergeant Major) Sergeant Loke (陆上士), Brother (兄弟) Captain (NS) - Koh Long Bin (Officer Commanding) Captain Koh (许军官), BB (宝贝), Busy Man (工作狂), Mr Xu (许先生) Young Version portrayed by Shaun Tan (陈凯轩) Corporal (NS) - Tan Kim Poh (Trooper) Lance Coperal Tan (陈下士), Daniel Tan, Daniao (大鸟), Play Boy (花花公子), Rich Kid (富二代), Little Airplane (小飞机) Captain - Sim Yi Xuan (Divisional Officer) Madam Sim (沈女官) Military Expert 2 - Pey Jing Yu (Senior Brigade Medic) Madam Pey (白女官), Brother (兄弟), Tom Boy (男人婆), Stainless Steel (铁金刚), Babe (美女) Officer Cadet - Yeoh Wei Guo (Midshipman) Gordon Yeoh, Mate/Buddy (伙伴), Recruit Yeoh, Sabo King Officer Cadet - Loke Xian Feng (Air Warfare Officer (C3) Ah Boy (阿Boy), Mummy Boy, Mate/Buddy (伙伴), Recruit Loke Air Force Engineer - Military Expert 1 Sim Yi Yun Air Force Engineering (AFE) (Maintenance) Cloudie Sim Teenage version portrayed by Cai Bei'er (蔡贝儿) Ms Lu (陆小姐), Little White Boat (小白船) Germaine Yeoh, B (宝贝), Lawyer Yao (姚律师) Navy (Sea) Captain - Seah Ming Yao (Divisional Officer) Roger That (收到) Police Deputy Superintendent (NS) - Lee Hong Xun (Patrol) Roger That (收到), Lawyer Li (李律师) Lieutenant Colonel - Yeo Yongzheng Fighter SQN (Commanding Officer) Michael Yeo Auntie Hua (花姐) Uncle Rong (荣叔) Mount Fuji (富土山) Sweetheart (甜蜜) Navy (Sea) Jeff Navy (Sea) Navy (Sea) Part time Police Officer (NS) - (Patrol) Air Force (Air) Filming began in February 2017 and was completed in May.

The series was filmed in collaboration with the Ministry of Defence (MINDEF) and Ministry of Home Affairs (Home Team).