New Era Cap, Associated Press
In this undated publicity image released by New Era Cap, actors Alec Baldwin from "30 Rock," and John Krasinski, from "The Office," are shown in a television spot that pits them against each other as trash-talking Yankee and Red Sox fans.

NEW YORK — Yankee-Red Sox divisions run deep, even right through NBC's Thursday-night comedy schedule.

Alec Baldwin of "30 Rock" is a Long Island native and an ardent New York Yankees fan. John Krasinski of "The Office" hails from Newton, Mass., and is hopelessly devoted to his Boston Red Sox.

Though the two exist in separate TV lands on Thursdays — Baldwin as the executive Jack Donaghy in the New York headquarters of NBC, Krasinski as paper salesman Jim Halpert in Scranton, Pa. — they are currently meeting in popular commercials for headwear maker New Era.

In the spots, the two trash-talk like a typically arrogant Yankee fan and a typically overly dramatic Red Sox fan. Krasinski compares being a Yankee fan to rooting for fascism, to which Baldwin replies: "No, it's like being a huge fan of winning, which we do ... relentlessly."

"We thought it would be really fun because we are such big fans of both teams," says Krasinski. "He's definitely the epitome of someone who grew up in New York. And I think I'm somewhat of the epitome of someone who grew up in Boston."

Baldwin and Krasinski became friends while making 2009's "It's Complicated." Each speaks highly of the other.

Krasinski calls Baldwin "one of the truer friends you can ask for in this business." Baldwin says Krasinski is going to be "one of the great romantic leading men in movies."

"There's no one I could have done this with other than John," says Baldwin. "I just love John. He encapsulates the Red Sox fan, people who are into super-religious symbolism, people who do a lot of praying. Red Sox fans are people that have to do a lot of talking to God."

The ads are being featured on broadcasts of Red Sox-Yankee games and will continue throughout the season. A new one will debut during Friday's game between the teams.

As the year goes on, their disagreements will mount. Says Baldwin: "I smashed this cake one day."

"There's a gradual evolution towards how we deal with our friendship in the midst of all this," says Krasinski. "There's definitely going to be some pyrotechnics involved. There's definitely violence, too, which is luckily hilarious violence and not real violence. It escalates pretty quickly."

So far, the Yankees have jumped out to a division lead while the Red Sox stumbled early on — though the Sox have since turned it around.

"He's much more excited with how the spots are going right now," says Krasinski. "I'm fine. I'm fine to take the egg on my face right now and hopefully celebrate at the end."

Baldwin is fittingly confident: "I want the Yankees to prevail and I want the Red Sox to do what the Red Sox always do."