Steely Dan legend Walter Becker has died of unknown causes at the age of 67.

The sad news was revealed with a post on his official website, which paired childhood and recent photos of Becker with the caption "Walter Becker Feb. 20, 1950 - Sept. 03, 2017."

Becker's longtime bandmate Donald Fagen has also issued a statement confirming Becker's death, and promising to "keep the music we created together alive as long as I can with the Steely Dan band."

Concern for Becker's health was raised earlier this summer when he missed both of Steely Dan's July appearances at the Classic West and Classic East music festivals. During a press conference the following month, Fagen stated that Becker was "recovering from a procedure and hopefully he'll be fine very soon." He offered no further specifics on Becker's ailment or condition.

Together with his longtime Steely Dan collaborator Donald Fagen, Becker brought revolutionary new levels of sophistication to rock and roll songwriting and studio production, incorporating elements of jazz, latin music, R&B, soul and traditional pop.

Becker was born in 1950 in New York City, and grew up there and on Long Island. Although he originally picked up the saxophone, he soon switched to guitar and took lessons from his neighbor and former Spirit member Randy Wolfe.

While attending Bard College, Becker met Fagen, and the two formed and played in several groups — including the Leather Canary, which featured classmate Chevy Chase on drums. Becker soon dropped out of school to focus exclusively on his songwriting partnership with Fagen.

In 1971, the duo left Brooklyn, where they had been working, for California. It’s there that Steely Dan was born. Initially, touring as a full band with Becker on bass, by 1974 they quit the road altogether and redirected their energies to studio work.

A year after the release of their seventh album, 1980's Gaucho, the duo called it quits. Becker went on to produce albums for Rickie Lee Jones, Michael Franks, Fra Lippo Lippi and China Crisis.

12 years later, Fagen and Becker reunited for a Steely Dan tour. At the time, the pair also produced each other’s solo albums — Fagen's Kamakiriad in 1993 and Becker’s 11 Tracks of Whack in 1994. 2000's Two Against Nature, Steely Dan’s first new album in 20 years, earned them four Grammy awards. The following year, they were inducted into the Rock and Roll Hall of Fame. In 2008, Becker released a second solo album, Circus Money, backed by members of Steely Dan.

Rocker Deaths: Artists We Lost in 2017