CHICAGO (Reuters) - The NFL's most intense, glamorous and longest rivalry enters uncharted territory Sunday when the Green Bay Packers visit the Chicago Bears for the NFC championship.

For the first time since they began lining up against each other in 1921, the bitter NFC North adversaries will meet with a berth in the Super Bowl on the line.

"It doesn't get any better than the NFC championship coming down to the Packers on our turf," Bears coach Lovie Smith told reporters. "It's the Packers and the Bears to finish it up."

The game will be played in frigid temperatures at 87-year-old Soldier Field, giving NFL romantics the perfect conditions for the highly anticipated match-up.

With temperatures expected to be hovering around 20 degrees (minus 6 Celsius) at gametime with a chance of snow, the field, one of the NFL's worst, could play a role in the outcome.

Even President Obama is keeping a close eye on the game, vowing to follow the Bears to the Super Bowl in Dallas if they can beat the Packers.

"If the Bears win, I'm going, no doubt," Obama, a former community organizer in Chicago, said this week following an Oval Office meeting with Chinese President Hu Jintao.

The Packers split the year's series with the NFC North champion Bears (12-5), and won the match-up 10-3 just three weeks ago in the regular season finale.

But Green Bay (12-6) needed the win to get into the playoffs so there may not be too much to be gleaned. The Bears beat the Packers 20-17 in Week Three of the regular season.

To do that, they will have to win the Super Bowl's Vince Lombardi Trophy, named for the Packers coach who won five NFL championships.


Ironically, before they can compete for the Lombardi Trophy, they will have to beat Chicago and win the NFC's George Halas Trophy, named for the former Bears owner and coach.

"We're half-way there," said McCarthy. "We talked about 16 quarters as a football team. We've completed eight of them. And we need to capture these four in Chicago, and it puts us closer to getting that picture on the wall.

"It's a goal that's still in front of us and it was a goal when we started and it's still a goal today."

Despite playing in Chicago on Sunday, the Packers, led by quarterback Aaron Rodgers, are about a 3.5-point favorite to beat the Bears and reach the Super Bowl on February 6.

The Packers won their last two regular-season games to reach the postseason and then beat the Philadelphia Eagles 21-16 and Atlanta Falcons 48-21, both on the road. Chicago had a bye in the first round of the playoffs before beating the Seattle Seahawks 35-24 at Soldier Field.

"They know who we are," says Packers Pro Bowl receiver Greg Jennings. "They know how we operate. And we know who they are. We know how they operate.

"Obviously we've played them twice already. Two close games that could have gone either way. And here we are again, when it really counts this time."

The teams have met 181 times (with Chicago holding a 92-83-6 edge) though just once in the postseason, a 33-14 Bears victory in 1941.

Chicago Pro Bowl linebacker Brian Urlacher conceded Sunday's game is "a big deal."

"We have a lot of history with them," he said. "We don't like them and they don't like us. It's a big challenge and we're excited."

(Writing by Steve Ginsburg in Washington; Editing by Rex Gowar)