Making her little monsters proud! Lady Gaga doesn't need backup tracks in order to receive a standing ovation from an audience. The singer put on a stellar performance when she covered John Lennon's song "Imagine" at the 2015 European Games Opening Ceremony on June 12.

The "Applause" singer, 29, belted out the 1971 classic to over 70,000 people while playing the piano, which was draped with colorful flowers. The fresh-faced star wore minimal makeup, a white outfit, and kept her blonde tresses down.

Lady Gaga previously blew fans away when she paid tribute to The Sound of Music during the 87th Academy Awards in L.A. on Feb. 22. She sang a medley of songs from the 1965 film, including "The Hills Are Alive," "Climb Ev'ry Mountain," "My Favorite Things" and "Edelweiss." Julie Andrews surprised the audience by embracing the star on stage afterward.

"Lady Gaga was unbelievably generous," the legendary actress, 79, said after the star-studded night. "I've always been a fan, but I made a new friend because she's lovely. She called and asked if I would object in any way of her doing the medley in any way and I said, 'Of course not.' And she sang them in the keys that I originally sang them in the movie in honor — and a tribute to me."

Watch the video above!

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