Anyone who has followed 'Late Show With David Letterman' over the years knows that the host is a huge fan of Foo Fighters, but after the cameras shut down for the TV audience one night earlier this week, Letterman revealed one of the reasons he's a big fan of the band.

In an Internet-only video, Letterman took the mic to introduce the song 'Miracle.' Speaking about Foo Fighters, the late night host offered, "They have crossed my path in many ways unexpected and expected and as a result, each and every year they grow to me more and more as human beings and talented musical artists."

One of those unexpected ways they've been a part of his life involves a treasured Letterman family moment. The host revealed that he was looking for something that he and his son could experience together and decided that they could both learn how to ski. At the end of their training, the instructor offered to take video of them and their time skiing down a mountain. Letterman recalled that when the video came back, it was soundtracked with the Foo Fighters song 'Miracle,' which has since become one of his favorite songs. After the touching revelation, the group played the track for Letterman and the 'Late Show' audience. Watch the full video with Letterman's introduction above.

Meanwhile, the stream of special guests continued Thursday night with Foo Fighters inviting Cheap Trick guitarist and 'Sound City' player Rick Nielsen to join them on the Ed Sullivan Theater stage. The group chose to cover Cheap Trick's 1978 song 'Stiff Competition,' with Taylor Hawkins, in a Robin Zander-styled white suit, stepping out from behind the kit to take on guest vocals, while Dave Grohl sat in behind the kit.

Foo Fighters kick off the first episode of their HBO documentary series 'Sonic Highways' at 11PM ET this evening. After the 'Sonic Highways' episode concludes, you can head over to the HBO Facebook page where you can stream a live Foo Fighters concert from the Cubby Bear in Chicago.

Watch Foo Fighters + Rick Nielsen Perform 'Stiff Competition'

You Think You Know Foo Fighters?