Advertising firm Allen & Gerritsen (A&G) is planning to move its 120-person office from Watertown to more than 33,000 square feet in Boston’s emerging Innovation District on the South Boston waterfront by next September.

A&G, named one of the best places to work in the U.S. by Advertising Age, said in a statement that it intends to hire approximately 50 new employees once its move to 2 Seaport Lane is finalized.

"Creativity, technology and curiosity are at the heart of Allen & Gerritsen’s core," said A&G CEO Andrew Graff. "That’s why the Innovation District will be the perfect home for our agency."

Jones Lang LaSalle represented the landlord in the transaction. A&G was represented by John Butterworth of CB Richard Ellis, according to a spokeswoman for A&G.

"Allen & Gerritsen is a forward thinking advertising agency, a company that is driving innovation," Boston Mayor Thomas M. Menino said in a statement. "Their business will benefit from collaborating in close proximity with companies such as Vertex Pharmaceuticals, AisleBuyer, Communispace and Babson College. I am thrilled that they are bringing 120 new employees, and adding 50 after their move, to the Innovation District – this is great news for Boston."