The Sound of Music 50th Anniversary

Oscars 2015: Julie Andrews "Deeply Honored" by Lady Gaga's 'Sound of Music' Tribute

Lady Gaga's Sound of Music medley at the 87^th Academy Awards was notable for many reasons -- namely, how stripped-down the whole affair was, with the pop star's beautiful voice taking center stage instead of the theatrics of her early career. The cherry on top was when Sound of Music star Julie Andrews came onstage afterward and embraced Gaga with a wide smile on her face.

It appeared that Andrews was just as in awe of the performance as the audience was -- and as it turns out, she was.

Christopher Plummer Skipped the Oscars Because 'It Was a Tribute to Julie Andrews'

The night wasn't supposed to be about Captain Von Trapp.

That's why Christopher Plummer, who played the man of Maria's dreams in The Sound of Music, skipped the 50th anniversary tribute to the 1965 Best Picture musical on Oscar night last Sunday.

"I couldn't be there for personal reasons, and secondly I didn't want to," Plummer, 85, tells PEOPLE exclusively. "It was really a tribute to Julie. It's her movie. It's a terrible phrase we have in England but if I had appeared there I would have looked like a spare prick at a wedding. That's the most perfect description of how I would have looked."

Plummer did watch the show, however, and was blown away by Lady Gaga's rendition of the title song.

"I thought Lady Gaga sang absolutely wonderfully," said Plummer, who won his first Oscar in 2012 for Beginners. "She knows how to do two styles. She knows the old way and she knows the new way and she was so faithful to the style of the story and the song. Julie looked terrific. I was thrilled it was a tribute to her and so it should be."

Asked what pop culture phenom he would have liked to sing on his behalf if the Oscars featured his movie solo "Edelweiss" instead, Plummer gets a little tongue-tied.

"I don't know enough about the rock scene, really," Plummer admits. "I'm an old jazz fan."

Plummer and Andrews will participate in this year's TCM Classic Film Festival, which will run March 26-29 in Hollywood. The festival will kick off with a screening of The Sound of Music.