Don Lemon had a "nasty" exchange with his "CNN This Morning" colleague Kaitlan Collins in what appears to have been a rift between the two on-air personalities. 

On Dec. 8th, during CNN's breaking news of Brittney Griner's release from Russia, there were multiple on-air instances where Collins attempted to interject while Lemon was speaking. At one point, Lemon wagged his finger above the desk and told her "standby one second."

While off-air, however, 56-year-old Lemon got "nasty" at 30-year-old Collins, scolding her for "interrupting" him, which left co-host "visibly upset," a source who witnessed the exchange told Fox News Digital. 

CNN'S DON LEMON DENIES HE'S BEING DEMOTED AFTER LOSING PRIMETIME GIG FOR ENSEMBLE MORNING SHOW

Word of the incident reached CNN boss Chris Licht, who urged Lemon to "take a beat," the source said. 

Lemon did not appear on the Dec. 9 broadcast with co-host Poppy Harlow telling viewers, "Don has the day off."

The New York Post first reported on the incident, which a CNN spokesperson told Fox News Digital is "wildly overblown."

"Don, Kaitlan and Poppy were friends before they were co-anchors, and they remain friends today," the CNN spokesperson added.

The Post's report suggested there was some trouble in paradise between Collins, widely seen as a rising star at CNN, and Lemon, who was shuffled into mornings after struggling in primetime.

CNN'S DON LEMON-CENTERED MORNING SHOW SUFFERS STEADY VIEWERSHIP DECLINE THROUGH THREE MONTHS

"The following night, the three co-hosts were slated to get drinks and arrive together at a White House Christmas party for the press, a source said. But the pre-party gathering never happened after the emotional day and they trickled in to the bash separately, an insider with knowledge said. After the party, Lemon had a late-night dinner with his agent, Jay Sures, according to sources," the Post reported, adding, "The situation was especially awkward because Collins… is also represented by the powerful and well-connected Sures."

"At this point, Kaitlan wants to be on set with Don as little as possible," the source told the Post. "It’s messy." 

The week prior, Lemon clashed with Collins as well as Harlow in a debate over the pay disparity between professional male and female soccer players.

Collins told Lemon he wasn't "looking at the root of the issue" at how society historically platformed men's sports versus women's.

FOX NEWS CRUSHES CNN, MSNBC VIEWERSHIP AS DON LEMON’S MORNING SHOW HAS WORST WEEK SINCE LAUNCH

"It's because [men's soccer] is more interesting to watch!" Lemon exclaimed. "It just is!"

"That's not true," Collins responded, looking visibly bothered by the comment, which Lemon alleged was a joke.

The two of them continued their spat going into the commercial break.

Back in September, Licht pulled Lemon from CNN's primetime lineup for the launch of a new morning show replacing the long-struggling Jeff Zucker-era program "New Day," hoping to recreate his success after he launched "Morning Joe" on MSNBC and revived "CBS This Morning."

Lemon repeatedly insisted at the time that he wasn't being demoted despite going from a solo gig in the one of the most coveted time slots to a morning program with two other co-hosts. 

CLICK HERE TO GET THE FOX NEWS APP

"CNN This Morning," which debuted in November, stumbled out of the gate averaging just 454,000 total viewers that month. In December, it managed only to average 389,000 viewers, dropping further to a 373,000 average viewers in January, losing nearly 20% of its audience in the process. 

"New Day" averaged 413,000 daily viewers in 2022 before it was canceled to outdraw its Lemon-helmed replacement’s January viewership by 10%. 

All data courtesy of Nielsen Media Research. 

Fox News' Brian Flood contributed to this report.