Singer/songwriter and former Wilco member Jay Bennett died in his sleep Sunday at his home in Urbana, IL. He was 45.

"We are profoundly saddened to report that our friend died in his sleep last night," reads a statement posted at his label Undertow Music Collective's website. "Jay was a beautiful human being who will be missed. "

A cause of death was not immediately available and an autopsy was planned, according to the Chicago Sun-Times.

The multi-instrumentalist and producer was a member of Wilco from 1994 until 2001, and is generally given credit for helping steer the band's sound from its twangy, alt-country roots to the more experimental and avant-garde sound that first emerged on 1996's "Being There," and became more dominant on 1999's "Summerteeth" and 2002's "Yankee Hotel Foxtrot."

Tensions between Bennett and Wilco leader Jeff Tweedy surfaced early on, however, and culminated in Bennett's firing from the band in 2001 following the "Yankee Hotel Foxtrot" recording sessions. The increasingly tense relationship between the two is documented in director Sam Jones' 2002 behind-the-scenes film, "I Am Trying to Break Your Heart: A Film About Wilco."

Earlier this month, Bennett sued Tweedy, claiming he was owed royalties for songs during his seven years and five albums with the group. Bennett also claimed he was owed money from Jones' film.

"We are all deeply saddened by this tragedy," Tweedy said in a press statement released yesterday. "We will miss Jay as we remember him--as a truly unique and gifted human being and one who made welcome and significant contributions to the band's songs and evolution. Our thoughts go out to his family and friends in this very difficult time."

After leaving Wilco, Bennett released four solo albums, including his latest, "Whatever Happened I Apologize," which surfaced last November. In addition to his solo work, Bennett was an in-demand session player, appearing on albums by Sheryl Crow and Allison Moorer, among others.

Bennett had suffered from various health problems over the past year and was due to undergo hip replacement surgery, according to his MySpace blog.

"I still don’t know exactly when my surgery will be, but I have learned a good deal about the procedure, and that has helped to make me MUCH less fearful," Bennett wrote on the blog. "The double dose of anxiety caused by the pain, and the quite natural fear of the invasive surgery itself, really had me in its grip for a while, but now it only comes in waves.

"Once I am able to get a down payment of sorts together and actually have the surgery performed, I have been told that I then have only about six to eight weeks of physical therapy before I should be operating at approximately 80% capacity."