Robert Downey Jr completes awards season sweep with Oscar win

Robert Downey Jr (Chris Pizzello/AP)

Robert Downey Jr completed his clean sweep of awards season as he was named best supporting actor at the Oscars for his role in Oppenheimer.

The Iron Man star won for his performance as Lewis Strauss, head of the Atomic Energy Commission in the epic biopic about J Robert Oppenheimer, the theoretical physicist described as the father of the atomic bomb.