NBC News has lost one of their own.

NBC News Washington Bureau Chief TIM RUSSERT has died at 58, according to NBC News.

TOM BROKAW interrupted afternoon programming for a special report, announcing: "It is my sad duty to report this afternoon that my friend and colleague Tim Russert collapsed and died earlier this afternoon."

Brokaw, who called "Meet the Press" host Russert "our beloved colleague, one of the premier journalists of our time," went on to say, "This news division will not be the same without his strong, clear voice. He'll be missed as he was loved: greatly."

Russert's personal physician, DR. MICHAEL A. NEWMAN, announced on MSNBC Friday night that an autopsy had been conducted and it was determined that the affable 58-year-old journalist had passed away due a heart attack resulting from asymptomatic coronary artery disease.

MSNBC dedicated its afternoon broadcast to correspondents like Brokaw, BRIAN WILLIAMS, ANDREA MITCHELL, KEITH OLBERMANN and DAVID GREGORY, who shared their favorite work and personal memories of Russert.

The tribute to Russert will continue tonight when Brokaw anchors "Remembering Tim Russert," a NBC News special at 10 p.m. The hour-long report will look back at Russert's relationship with his dad and his roots in Buffalo, N.Y., as well as reviewing his career highlights while colleagues and politicians share their memories.

President GEORGE BUSH said in a statement Friday afternoon: "LAURA and I are deeply saddened by the sudden passing of Tim Russert. Those of us who knew and worked with Tim, his many friends, and the millions of Americans who loyally followed his career on the air will all miss him.

"As the longest-serving host of the longest-running program in the history of television, he was an institution in both news and politics for more than two decades. Tim was a tough and hardworking newsman. He was always well-informed and thorough in his interviews. And he was as gregarious off the set as he was prepared on it.

"Most important, Tim was a proud son and father, and Laura and I offer our deepest sympathies to his wife MAUREEN, his son LUKE, and the entire Russert family. We will keep them in our prayers."

According to NBC, Russert was born in Buffalo, NY, on May 7, 1950. After graduating law school, he was involved in the political campaigns of Senator DANIEL PATRICK MOYNIHAN (D-New York) and New York Governor MARIO CUOMO, before he joined NBC News in 1984.

He took the helm of television's longest-running show, "Meet the Press" in 1991 and was also NBC's Washington Bureau Chief. He was awarded numerous professional awards for his work in journalism, and also was the recipient of 48 honorary doctorates.

Russert, who won an Emmy in 2005 for RONALD REAGAN funeral coverage and was named one of Time magazine's 100 most influential people of 2008, also wrote two books: Big Russ and Me, (2004) and Wisdom of Our Fathers (2006).

He was also an active philanthropist, serving on the board of directors for the Greater Washington Boys and Girls Club, and an organization called America's Promise -- Alliance for Youth.

Russert is survived by his wife of over 30 years, Vanity Fair writer MAUREEN ORTH, his son, LUKE, and his father, TIM "BIG RUSS" RUSSERT, SR.