Matthew McConaughey in Dallas Buyers Club
02/20/2014 AT 12:10 PM EST
has called his Dallas Buyers Club transformation
a physical and spiritual journey. But there was a single moment while playing AIDS activist Ron Woodroof that he says felt like "a soul punch."
Appearing on a new episode of Inside the Actors Studio
that airs Thursday night (8 p.m. ET) on Bravo, the Oscar nominee
discusses a line that will stay with him forever.
"There's a scene in this film where Ron goes, 'I'm dying.' Those two words, 'I'm d-y-i-n-g,' I didn't expect it but it just ... hit me and it floored me," McConaughey tells host James Lipton
Up for Best Picture at the 2014 Academy Awards
on March 2, Dallas Buyers Club
follows HIV-positive outlaw Woodroof as he smuggles medicine into Texas and fights pharmaceutical companies peddling a dangerous AIDS treatment.
McConaughey famously shed
almost 50 lbs. for the role. Though he has since regained his muscular figure, the actor says he will always empathize with Woodroof's realization that he was approaching death.
"Saying those worlds floored me in a way that I think definitely grounded me since then in a different way than I was before," he says. "Maybe it's my own mortality, but it was a moment personally for me, that I found through Woodroof, that's never gonna leave me."
Watch a clip below, and catch the full interview Thursday on Bravo's Inside the Actors Studio