Know we know why Larry King lunged at Katie Couric.

Old people dig her....along with the rest of daytime TV.

The NY Daily News writes that it turns out that daytime TV shows, many of which — like “TMZ” hope to attract young, wealthy viewers — appeal to some of the oldest viewers of all, according to Nielsen.

It’s Madison Avenue’s worst nightmare.

For example, if you are 59 years old and watch Katie Couric’s daytime show, you actually bring down the average age of her viewership.

Nor does Katie stand alone with a mature audience. A new Nielsen measurement says the 40 first-run syndication shows have a media viewer age of 56.9 — meaning half the viewers are above that age and half are below.

The show with the youngest media age is “Dish Nation,” the daily roundup of bits from morning radio shows that include Scott and Todd from WPLJ (95.5 FM).

“Dish Nation” has a median viewer age of 45.2, making it one of just eight first-run syndicated shows whose media age falls into the 18- to 49-year-old bracket all TV providers fervently court.

It’s not a particular scandal that audiences for syndicated shows, most of which run in the daytime, skew older — because many younger viewers are in school or working during the day.

Still, it illustrates a challenge for syndication, because if a show isn’t getting a lot of younger viewers, it needs a larger total viewership in an increasingly fragmented TV landscape.

Here are the shows with the youngest average viewer age:

“Dish Nation,” 45.2

“Excused,” 45.4

“TMZ,” 46

“Maury,” 47

“Steve Wilkos,” 47.9