Jerry Seinfeld (search) is back on NBC!

But it's only for one night and only for 10 minutes.

Seinfeld, the former Thursday king of NBC, is returning as part of an unusual primetime promotion for American Express.

The 10-minute promo is scheduled to run from 8:42 p.m. to 8:52 p.m., starting with the television premiere of the "Seinfeld & Superman" (search) series that premiered in March on americanexpress.com.

The "web-i-sode" - titled "A Uniform Used to Mean Something" and running about four minutes - has Seinfeld and Superman (voiced by Patrick Warburton, "Seinfeld's" David Puddy) hanging out together in Manhattan.

But tonight's elaborate promo has also been designed to generate excitement for the second web-i-sode, "Hindsight is 20/20," which will have Jerry and his pal Supe on a road trip.

"Hindsight" premieres today at noon on the Amex Web site.

Neither Amex nor NBC would say whether the 10 minutes of primetime - some of the priciest real estate in all of television - was purchased outright by American Express.

The promo will be sandwiched between a "supersized" rerun of "Friends" and a re-airing of the 66-minute "Friends" (search) series finale.

Those 10 minutes would be worth nearly $9.5 million based on reported rates for 30-second spots during regular episodes of "Friends" - $473,500, according to Advertising Age.