Really?!

Matt Damon was presented the Best Actor award by Robert De Niro at the National Board of Review Awards on Tuesday, Jan. 6 — and he revealed something super surprising during his acceptance speech!

The Martian star, 45, admitted that Sylvester Stallone's acting in his very own Rocky script is what inspired him and Ben Affleck to insist they star in their breakthrough script for the 1997 iconic film Good Will Hunting.

RELATED: Sylvester Stallone Shares an Adorable Selfie With His Three Gorgeous Daughters — See the Pic!

matt damon and ben affleck (photo credit: getty images)

Ben and Matt in August 2015.

Wow – who knew?!

Though the famous duo went on to win an Oscar for their outstanding screenplay in 1998, the 69-year-old Rocky star has never taken home an Oscar or Golden Globe, despite being nominated for both in 1977.

Now, almost 40 years later, Sylvester is returning to the Golden Globes as a nominee for his outstanding performance in Creed.

"When [the nomination] happened in '77, I wasn't in the moment," Sylvester told Entertainment Tonight. "I didn't really understand how hard it is or how difficult. Now, I'm just savoring it all."