The pop newcomers were named the recipients of the ASCAP Vanguard Award for helping to shape the future of music, and superfan Julia was on hand to present the prize to the duo at the Los Angeles event.
Eilish and Finneas follow in the footsteps of previous honourees including Janelle Monae, Portugal. The Man, and St. Vincent, and they proved why they had been saluted by staging an acoustic performance, which included versions of Billie's hits "When the Party's Over" and "I Love You".
Officials at ASCAP (the American Society of Composers, Authors and Publishers) also celebrated the work of Pop Music Songwriter of the Year Louis Bell, who was praised for contributing to chart smashes like "Havana" by Camila Cabello and Young Thug, Post Malone's "Better Now", and "Wolves" by Selena Gomez and Marshmello.
Zedd's Maren Morris and Grey collaboration "The Middle" was hailed as Song of the Year, earning an award for the dance DJ and co-writer Stefan Johnson, while Drake and his songwriters Ronald 'Cardo' La Tour, Matthew 'Boi-1da' Samuels, and Noah '40' Shebib picked up the Most Streamed Song of the Year title for "God's Plan".
There were also top prizes for Electric Light Orchestra star Jeff Lynne, who was presented with the Founders Award for songwriters and composers by fellow Rock and Roll Hall of Famer Joe Walsh, while Blondie were feted with the Golden Note Award in celebration of their career achievements.