Preview clips of night talk shows

This has bugged me for a long time. Maybe someone here can help.

I'm watching the Dolphins-Patriots on CBS and a Letterman commercial just came on. Guest this week include Matt Damon, Clint Eastwood and kid scientists blowing stuff up. We saw clips of all of the above.I've seen the same thing with Leno commercials advancing upcoming shows.

Question: When did Damon, Eastwood and the kids tape those segments, which presumably are happening this week?

 

and it's not like it's one show. i don't think damon and eastwood are appearing on the same night.

i don't even have a decent theory. i guess they tape it, but the monologues often include that day's news. what am i missing here?

 

i've considered that. i guess i'll have to see if the kid scientists who blew something up on the clip, are the same kid scientists who blow something up this week.

 

They said it was Eastwood's first appearance on the show.

Great question.

 

The Eastwood clip wasn't from Letterman's show. It looked like it was from a 60 Minutes interview.

 

I gotta agree it's a good question because I've often wondered this too. Apparently a few people have attempted to poke holes in this one example, but there are plenty of times where it has definitely seemed like the interview already took place, but I can't think of any specific example off the top of my head.

 

I know one day a week Letterman tapes two shows, but I think it's two shows on Monday and the second airs Friday. When I could remember which one it was, I did notice that the monologue that night was a little more canned.

 

I believe Letterman and Leno tape their shows at like 5pm local time.

 

On Sunday?

 

Letterman tapes two shows Thursday night; the second one runs Friday night.

I am almost 100 percent postive that the preview clips are from previous appearances.

 

Preview clips for the week are from previous appearances or, in Eastwood's case, from another show entirely. As far as the kid scientist bit goes, it is possible it was filmed last week and put into this week's show. I know at one Letterman taping I went to, he and Larry King did a bit that wasn't in that night's show but was put into a show the next week. Either that, or they've had kid scientists blowing stuff up before and used an old clip.

On the nightly previews, they just show a clip from that afternoon's taping. In Letterman's case, they open the theater doors at 4 p.m., seat everyone, have a warm-up act and then start the show at like, 4:30 or 5 p.m. They have plenty of time to cut together a commercial for that night.