(Tom Brady article updated with additional information on his endorsement deal with Under Armour.)

NEW YORK (

TheStreet

) -- Tom Brady has signed an endorsement deal with

Under Armour

(UA) - Get Report

after his contract with

Nike

(NKE) - Get Report

expired.

As a part of the endorsement deal, the New England Patriots quarterback will receive a stake in the company, the size of which has not been disclosed.

New England Patriots quarterback Tom Brady

"Tom Brady represents a lot of what Under Armour is all about," Under Armour founder and CEO Kevin Plank said. "He's humble and hungry and continues to be focused on winning and getting better every single day. We're proud to have him in our brand as he continues to re-write the NFL record books."

Brady will appear in Under Armour commercials and print advertisements beginning early 2011. He will also wear Under Armour apparel and footwear during training and will debut a new pair of cleats in upcoming football games.

"I am very excited to team up with Kevin Plank and the Under Armour family," Brady said. "It was important for me to align with a brand that shares my values and helps me perform at my best. Under Armour makes cutting-edge products for the next generation and for athletes who compete at the highest level."

The Maryland-based sport apparel and accessory company is 5% of the size of Nike.

Under Armour shares

are up nearly 85% in the past year, and are up almost 2% today to around $51.15.

-- Written by Theresa McCabe in Boston.

>To contact the writer of this article, click here:

Theresa McCabe

.

>To follow the writer on Twitter, go to

@TheresaMcCabe

.

>To submit a news tip, send an email to:

tips@thestreet.com

.

Disclosure: TheStreet's editorial policy prohibits staff editors and reporters from holding positions in any individual stocks.