In what I hope is my last ever post about Frozen, Pearl Jam showed they're fans of the film on Friday at the San Siro in Milan.
In the middle of Daughter, the band broke into the refrain from Let it Go, the Oscar-winning song from the film.
In the past, Pearl Jam has used the same space to break into Pink Floyd's Another Brick in the Wall which meshed fairly seamlessly. I'm not a much of a Pearl Jam fan, but I've always liked their cover songs (especially Last Kiss), so this works for me.
There are two pretty crappy cell phone versions going around on YouTube, but I pulled the song off of a much better audience recording from an ROIO site. The show should be available officially from Pearl Jam shortly if you're into that kind of thing.
The refrain happens about 4:50 into the song if you want to skip.