David Letterman makes awkward mistake as he defends Taylor Swift from NFL critics

David Letterman has rushed to Taylor Swift's defence as she's bashed by NFL fans - but an awkward mistake has had fans in stitches.

In the wake of the ongoing grief the singer's been getting, Letterman rushed to Swift's defence and posted a video to Instagram.

While his intentions were more than pure, the 76-year-old made a hilarious mix-up over who Swift was actually dating. Check it out below:

In case you've been living under a rock these past few months, Swift is dating Kansas City Chiefs tight end Travis Kelce and has been spotted at several of his games.

But some NFL fans are growing tired of seeing the 'Cruel Summer' hitmaker's face on the screen all the time, with some even going as far as accusing the 34-year-old singer of 'ruining' the sport.

However, the reported $330 million boost Swift has added to her beau's football team and the NFL's 'brand value' may have some Chiefs fans changing their tune.

Away from some disgruntled football fans' grievances, most people are in favor of Swift and Kelce's blossoming romance - David Letterman included.

Speaking about Swift's influence, Letterman said in the video: "I don’t think in the history of show business, in the history of pop culture, that we have witnessed anything like this.

"Tremendous, she fills stadiums around the world and puts on a three-hour show."

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Noting her romance with Kelce, Letterman hilariously mixed up the footballer with Frasier star Kelsey Grammer.

"So now here is Taylor Swift who is a glowing bright light of goodness in the world and she starts dating Kelsey Grammer," he said.

Some people out of shot immediately clocked the mix-up, with one interrupting: "Kelsey Grammer?"

While another said: "An interesting pairing."

Letterman carried on undeterred: "People go crazy. And the Kelsey Grammer people go oh no, no, don’t bother us, we are all caught up in football, we don’t want Taylor in football.

"And the Taylor Swift people, the Swifties, are saying we don’t want a footballer."

It's unclear if it was a genuine faux pas or if talkshow host did it for the laughs - but it went down a storm with his fans either way, so much so that many are calling for the 76-year-old to return to TV.

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One person wrote: "When you said Kelsey Grammar, it really cracked my egg!"

"Kelsey Grammer is jealous of Taylor and Travis," joked another.

Someone else gushed: "Such a smart funny insightful man. Using the confusion of the Kelsey Grammer thing as a comedy hook."

Calling for his Late Night return, another went on: "Dave, please come back to Late Night! We miss you."

"Lol Dave. We need you back to make sense of it all," echoed a different Instagram user.