Liam McIntyre said he had to work out to prove to Starz that he could handle he lead role on "Spartacus."
McIntyre replaced Andy Whitfield for the second season of the show, called "Spartacus: Vengeance," so Whitfield could battle non-Hodgkin's lymphoma. Whitfield died of the disease in September.
Also read: Starz Chris Albrecht: 'We All Thought Long and Hard' About Continuing 'Spartacus'
"From the start I think I was able to tackle the role because I knew he'd get better," McIntyre said at the Television Critics Association winter press tour Friday. When he learned of Whitfield's death, he said, "You can't imagine how sad that day was."
Network executives spent months deciding whether to keep the show going after Whitfield left -- and who should play him.
To earn the role, McIntyre had to work out intensely by lifting heavy weights -- sometimes while running, he said. Executives received regular updates on his physique, and eventually he beefed up enough to win them over.
"It was like nothing I'd ever experienced before," McIntyre said.