"Game of Thrones" was on TV for a long time, and a new clip from HBO's reunion special offers a stark reminder.

The touching sneak peak shows the special's host, Conan O'Brien, showing the cast footage from their time on the hit series, starting with the very early days. For the youngest cast members such as Maisie Williams (Arya) and Isaac Hempstead-Wright (Bran), there's material from when they were half as old as they are now. Not only is it adorable, it provides a very visual representation of the show's longevity.

Another fun facet of the clip is that it doesn't just show scenes from the series; there is also behind-the-scenes footage of the actors from the many years of filming.

"It's my first-ever filming of anything," a very baby-faced Kit Harington says at one point.

Watch below and see how the show's stars have changed.

The reunion special will be included in HBO's Blu-ray release of "Game of Thrones: The Complete Collection," which goes on sale Dec. 3.