"He keeps me calm," Clearley told PEOPLE at Thursday's Hollywood Reporter pre-Oscar bash in L.A. "I'm the nervous one. He's been to [award shows] before. I haven't. It's crazy!"
Renner, 39, a best actor nominee for The Hurt Locker, gave his mother an early taste of what to expect at the Academy Awards during Thursday's reception, held at mayor Antonio Villaraigosa's official residence. The two navigated the red carpet before TV crews descended on Renner, who has emerged as one of Hollywood's new leading men after his star turn in the Iraq war drama.
Even as she's adjusting to all the excitement, Clearley – who's still working on picking out a dress for Sunday – is "so proud" of Renner and his recent success. "It’s just been the most amazing thing," she said.
The 82nd Academy Awards will air live on ABC from the Kodak Theatre in Hollywood starting at 8 p.m. ET.