Country duo BIG + RICH are producing a new documentary about a battle in Vietnam in 1965 that claimed the lives of 48 US soldiers.

The documentary stems from the pair's timely new tune 8TH OF NOVEMBER, inspired by Niles Harris, one of the soldiers from the 173rd Airborne Brigade who survived an ambush by more than 1,200 Vietcong.

Big + Rich, real names Kenny Alphin and John Rich recently returned from a five-day trip to Vietnam, where they visited the battle site and some of those involved in the ambush.

Alphin explains, "We've had guys over there for the past several months locating the exact battlefield.

"We found the commander of the opposing army. We interviewed him. We found one of the Vietcong liaisons, the guys who were feeding information back and forth. We've learned so much. It's been so eye-opening."