The Russian composer Sergei Rachmaninoff has a songwriter credit for the power ballad “All by Myself.”
“All by Myself” is a classic power ballad. Eric Carmen first performed it in 1975, and Céline Dion famously covered it (firstly in 1996):
Eric Carmen wrote “All by Myself,” but he’s not the only credited songwriter. The Russian classical composer Sergei Rachmaninoff also gets a credit, and his estate gets twelve percent of the royalties from the song too.
How did this come about? Obviously Rachmaninoff was not penning hit singles thirty-two years after his death. Instead, Carmen borrowed the introduction and melody of the composer’s Piano Concerto No. 2 in C Minor for his song, turning them into the chorus and bridge of “All by Myself.” This was not plagiarism or a secret; Carmen did so believing that the music was out of copyright and therefore fair game. But this was not the case.
Soon after the song came out, Carmen received what I imagine was a rather irked message from Rachmaninoff’s estate. Piano Concerto No. 2 was of course still under copyright, and so the estate and the songwriter had to come to an agreement.
The result of that agreement is that song-writing credit for Rachmaninoff, and some decent royalties going to the estate. Falling into You, which contained Céline Dion’s cover of the song, is one of the best-selling albums in history, so those royalties are probably substantial.
[Thanks to Adam Neely.]
The Generalist Academy 
Obligatory 20 sec video from 2009 (or likely before):
Actually it was the 3rd movement of his Piano Concerto no. 2 – not second Symphony
You’re absolutely right – the second Symphony was used in Never Gonna Fall in Love Again. I have corrected the post.