Lester Holt is one cool dude.

The NBC Nightly News anchor recently posted a clip of his 22-month-old grandson, Samuel, calling him “Granddude” when he saw him on TV.

“That’s the first time I actually finally heard him say ‘Granddude,’ which I’ve been working on,” Holt said on Tuesday’s episode of “The Kelly Clarkson Show.”

He remembers the day it happened and said he was feeling in the dumps after what he thought was an average broadcast when his daughter-in-law sent him a text with the video.

“I just melt. You know, that’s the thing about kids. It takes you out of everything else going on in your life,” he said.

Samuel is the son of Stefan Holt, an anchor at NBC affiliate WMAQ in Chicago. Stefan Holt also has another son, Henry, 3, with wife Morgan.

The decision on what a grandparent wants to be called can be a tough one, but Holt said “Granddude” was steeped in the desire to still feel cool.

“I’d been working on ‘Granddude’ with him when my daughter-in-law was pregnant with her first baby,” he said.

“She said, ‘Well, what do you guys want to be called?’ And I said, ‘I think I want to be ‘Granddude’ because ‘grand,’ it bows to the fact that I’m older. But ‘dude’ says, ‘I still got a little bit. I still got a little,’ you know?

“So I’ve been working on it and it’s hard to say, so that was so great. I heard (it). ‘Yes, he said it!’ Even though it came out ‘grand-nude,’ he gets credit.”

Holt, 62, has embraced becoming a grandparent and has often shared photos of him spending time with Henry and Samuel when they visited him at work.

“Everything they say about being a grandparent is true,” Lester told Jimmy Fallon on “The Tonight Show” after Henry was born in 2018.

“You get to experience the love, the joy and then, at the appropriate time, you (gestures) ‘Here you go,’ and get a full night’s sleep … and not feel guilty about it.”