Brian Williams is taking a leave of absence from NBC News to undergo knee surgery, the anchor announced on Nightly News Thursday night.
Williams' temporary leave of absence will be starting sometime next week. Fittingly, he announced the news during a segment about chronic knee pain.
Pics: Stars in the Hospital
"By the way, if -- starting in a few days' time -- you don't see me around here for a while, this is the reason why," he said as an introduction to the segment.
This will be his fourth knee surgery. The longtime NBC anchor's knee problems stem from suffering an injury to his right knee in a high school football game in 1977.
Williams first announced he was undergoing the surgery during his appearance on The Late Show with David Letterman on July 17.
"I'm going in for the knee replacement. I'm going in for the whole titanium thing," he said.
Video: Allison Williams Impersonates Dad Brian Williams
Lester Holt will host on Nightly News while Williams is away.
Check out his announcement below.
Visit NBCNews.com for breaking news, world news, and news about the economy