Enya: She sang the iconic "May It Be" for *The Fellowship of the Ring* and "Aníron" for *The Two Towers*.
Annie Lennox: Her ethereal vocals grace "Into the West" in *The Return of the King*, a song that won an Oscar and Golden Globe.
Howard Shore: The film's composer, Shore also provided vocals for several songs including "Gollum's Song" and "Concerning Hobbits".
Others: Several other singers contributed to the film's soundtrack, including:
* Lilja Bloom: Performed the haunting "The Last Ship" in *The Fellowship of the Ring*.
* James Galway: His flute playing features prominently in "The Ride of the Rohirrim" in *The Two Towers*.
* The London Voices: A professional choir that contributed to many of the film's choral pieces.
It's worth noting that the films also use a lot of instrumental music, with Shore's score being a major component of the Lord of the Rings experience.