His announcement comes after Prime Minister Abiy Ahmed said he would go to the front to lead the war.
Speaking about the conflict, Gebreselassie said it is a proxy war and major powers in the west are supporting the rebel Tigray People’s Liberation Front (TPLF).
“The US and some countries in Europe are making a coordinated effort to snatch Ethiopia’s history as a symbol of black people,” he added.
The renowned Ethiopian long-distance runner and 2016 bronze medalist Feyisa Lelisa also announced decision to join the war what the government referred to as “existential war”
“Prime Minister Abiy Ahmed has made the right decision. And, I am ready to draw inspiration from the gallantry of my forefathers and repeat what they did in the Battle of Adwa at the frontline to save my country” Lelisa said.
The US and UK have urged their nationals to leave Ethiopia immediately, saying the fighting may move closer to Addis Ababa in the coming days.
The rebels earlier this week said that they had taken control of Shewa Robit, a town about 220km (140 miles) north-east of Addis Ababa.
However, since Prime Minister Abiy joined the front line, the rebel forces have been cleared from several towns including Shewa Robit.