The Taoiseach, as the Prime Minister is referred to in Ireland, has rejoined the medical register and will work one shift a week to help out during the pandemic, national broadcaster RTE reported.
Varadkar worked as a doctor for seven years before becoming a politician. He left the medical profession in 2013.
RTE reported that he re-registered as a doctor in March and offered his services to the country's Health Service Executive for one session a week. Varadkar will carry out phone assessments to free up staff for frontline work, according to RTE.
Ireland has almost 5,000 confirmed cases of coronavirus and 158 people have died of the disease in the country.
The country has been under a lockdown for over a week, with people not permitted to travel more than 2 kilometers from their homes.
People can leave their homes only when necessary: to purchase groceries and medicine, attend medical appointments, to take care of family or to engage in "brief" exercise.
Public and private gatherings amongst people from separate households are prohibited, and only essential workers -- including health and social care professionals -- are allowed to travel to and from work.
Varadkar is on his way out after the Irish parliamentary election yielded no clear winner. He resigned in February and said he'd continue as a caretaker leader.