Alan Kalter, the ginger-haired announcer and crooked straight man who served as David Letterman’s sidekick for two decades on CBS’ “Late Show,” has died.

He was 78.

“Late Show With David Letterman” announcer Alan Kalter in the studio in New York. Andrew Sullivan/Hearst Connecticut Media via AP, file

His wife, Peggy, confirmed his Monday death at Stamford Hospital in Connecticut to The Hollywood Reporter. A cause of death was not given.

Kalter took over as “Late Show” announcer in September 1995 after Bill Wendell’s retirement and was there until May 20, 2015, Letterman’s final show. He not only announced the guests and the host but also acted in sketches and delivered a comic one-liner after every show as the logo for production company World Wide Pants flashed across the screen.

“When our announcer of 15 years Bill Wendell retired, Producer Robert Morton came to my office with an audio tape containing auditions for several announcers,” Letterman told the Daily News in an email. “Alan’s was the first and only voice we listened to. We knew he would be our choice.”

His comic bits on Letterman included “Alan Kalter’s Celebrity Interview,” a show-within-a-show that resulted in some hilariously awkward moments. Letterman nicknamed his sidekick with monikers such as “Big Red” or “TV’s Uncle Jerry,” amplifying the comic effect.

Former colleagues paid tribute to the announcer and comic under the Twitter hashtag “RIPAlanKalter” as the news spread, with a favorite bit being that time he went off on his boss with a squirming Sarah Jessica Parker by his side as Kalter launched an expletive-laced takedown.

In a riff about “Dancing With the Stars,” Kalter spun literal comedic gold, swathed in lame and twirling madly in a faux failed bid to appear on the show.

“RIP Alan Kalter,” tweeted Letterman Show writer Bill Scheft along with a clip of one of Kalter’s bits on Letterman. “A lovely man, and as my old boss might say, a ‘perfect stooge …’ ”

“Whatever else, we always had the best announcer in television,” said Letterman, who now hosts “My Next Guest Needs No Introduction” on Netflix. “Did I mention he could sing? Yes, he could. He enthusiastically did it all. A very sad day, but many great memories.”