Fox News contributor Charles Krauthammer, a notable Pulitzer Prize winner, Harvard-trained psychiatrist and best-selling author, died on Thursday at age 68.

Krauthammer, who revealed in a heartbreaking letter earlier this month that his death was imminent, became well-known on Fox News Channel, frequently appearing as a guest commentator, as well as a nightly panelist on “Special Report with Bret Baier.”

Following word of his death, Baier posted on Twitter “I am sure you will be owning the panel discussion in heaven as well. And we’ll make sure your wise words and thoughts - your legacy - will live on here.”

“R.I.P. good friend,” he wrote.

Fox News Chief White House Correspondent John Roberts filled in as anchor for Thursday's "Special Report," however Baier dialed in and reflected on Krauthammer's life.

"It's really sad that we lost this voice in our national dialogue but know that his voice is going to live on on 'Special Report,'" Baier said, adding that Krauthammer "had an amazing sense of humor" and "an appreciation of people and ... what they were going through."

"Who Charles was was his thoughts, his knowledge, his wisdom and most importantly, his interaction with people," Baier said.

Roberts later tweeted, "Everyone at @FoxNews is saddened to report that our dear friend - a giant of our industry- Charles Krauthammer has passed away."

Brit Hume, senior political analyst for the channel, labeled Krauthammer's death “terribly sad news.”

“Fox News @ Night” anchor Shannon Bream tweeted that “There will never be another Dr. @krauthammer - never.”

“His brilliance, humor and kindness brightened the lives of everyone who was blessed enough to cross his path,” she continued. “He challenged me, inspired me and I find it hard to believe he's gone. #RIP My Dear Friend - I'm better bc of you.”

Dana Perino, who anchors "The Daily Briefing" and is a co-host on "The Five," said of Krauthammer that she "learned more from him than just about anyone in my life."

Fox News host Greg Gutfeld tweeted that Krauthammer was "one of the truly best, original thinkers on the planet."

Fox News anchor Abby Huntsman remembered Krauthammer as "a genius communicator" who was "one of America's greatest."

Mike Emanuel, chief congressional and senior political correspondent for Fox News, tweeted: "We love you, Charles @krauthammer. We miss you already. It was such a blessing to work with you all of these years. You and your family remain in my thoughts and prayers. #RIP."

Fox Business' Dagen McDowell said "Words fail to capture a man who was so brilliant with them."

"RIP Charles Krauthammer," Fox News contributor Byron York tweeted.

Fox News Senior Meteorologist Janice Dean tweeted "This is what's important. We lost a beautiful life today. Rest In Peace Charles Krauthammer. You will be missed but never forgotten."

Guy Benson, a Fox News radio host, tweeted "Like the very best of 'em, Charles Krauthammer leaves us wanting more. A lot more. #RIP."

Fox News contributor Stephen Hayes said he's "grateful beyond words" for his time with Krauthammer.

Fox News anchor Sean Hannity described Krauthammer as "an amazing man, a brilliant mind, and a incredible patriot" who "will be sorely missed."

Suzanne Scott, CEO of Fox News and Fox Business, in a statement said "We are deeply saddened by the loss of our colleague and friend, Charles Krauthammer. A gifted doctor and brilliant political commentator, Charles was a guiding voice throughout his time with FOX News and we were incredibly fortunate to showcase his extraordinary talent on our programs. He was an inspiration to all of us and will be greatly missed. Our thoughts and prayers are with his beloved wife Robyn and his son Daniel."

Fox News President and Executive Editor Jay Wallace tweeted the network was "celebrating the life of a brilliant man."

Fox News’ Elizabeth Llorente contributed to this report.