The late-night comedian appears in a season two promo for 'Years of Living Dangerously.'
David Letterman is getting back in front of the camera!
The former late-night host appears in a new promo for season two of Years of Living Dangerously -- an Emmy-winning docuseries about global climate issues -- in his first TV project since retiring from The Late Show last year.
WATCH: David Letterman Is Nearly Unrecognizable Sporting a Bushy Beard on the Beach
In the promo, Letterman speaks earnestly about the value of renewable energy sources before getting a little too close to a solar panel.
"Think about the coal-fired, dangerous, smoke-belching generating plants, and then you look at this and it’s friendly," the 69-year-old comedian says. "There’s something very appealing about this, and it’s smooth. Look at it -- I can touch it and it’s safe. I put my head right there on it."
WATCH: David Letterman Suggests 'Late Show' Should Have Gone to a Woman After He Retired
Unfortunately, the panel gets the best of our favorite impressively-bearded former talk show host. Check out the video below.
WATCH: David Letterman Comes Out of Retirement to Slam Donald Trump With 'Top 10' List
Meanwhile, Letterman admitted to NBC News' Tom Brokaw in June that he doesn't miss late night one bit.
"It’s interesting, I thought for sure I would. And then, the first day of Stephen [Colbert]’s show, when he went on the air, an energy left me and I felt like, ‘You know, that’s not my problem anymore,’” he shared. "I’ve kind of felt that way ever since. I devoted so much time to the damage of other aspects of my life. The concentrated, fixated, focusing on that. …It’s good now to not have that."
Watch the video below for more.
Season two of Years of Living Dangerously premieres Sunday, Oct. 30 on the National Geographic Channel.