Will Smith plays a conflicted man who decides to help seven strangers in the dramatic love story 'Seven Pounds' -- but he also holds a mysterious secret. ET has a first look at the film!

Will plays Ben Thomas, an IRS agent who embarks on an extraordinary journey of redemption by forever changing the lives of seven strangers, including Woody Harrelson as a blind man and Rosario Dawson as a woman with a failing heart.

"She's one of the seven strangers that [Will] meets and tries to affect positively," Rosario tells ET. "Through that interaction, she has an opportunity to change him positively and it grows very beautifully.

"It's very mysterious," she continues. "It's a really difficult film to describe, but there are certain moments between the two of them that are really authentic, and very romantic and beautiful, and I think that people will feel connected to it."

In theaters December 19, 'Seven Pounds' also stars Barry Pepper and Michael Ealy and reunites Will with his 'The Pursuit of Happyness' director Gabriele Muccino.

Watch ET for more with Will and the cast of 'Seven Pounds'!