"Your politics and campaign are clearly not aligned with the themes we portrayed in our series," Berg writes in the letter, challenging the GOP contender's use of "Clear Eyes. Full Hearts. Can't Lose."

Peter Berg, the writer-director of the Friday Night Lights movie and television series, is not pleased that Republican presidential candidate Mitt Romney has co-opted a phrase from the show for his campaign appearances.

In a letter to the Romney campaign sent Friday and obtained exclusively by The Hollywood Reporter, Berg calls the use of "Clear Eyes, Full Hearts, Can't Lose" an act of stealing. "Your politics and campaign are clearly not aligned with the themes we portrayed in our series," Berg writes in the letter. "The only relevant comparison that I see between your campaign and Friday Night Lights is in the character of Buddy Garrity -- who turned his back on American car manufacturers selling imported cars from Japan."

Read the Full Letter Here.

Romney has used the "Clear Eyes" phrase — which originated as a rallying cry for the high school football team on the FNL television series — in several campaign speeches, and it appears on his Facebook page. The Republican presidential nominee and his wife, Ann, are fans of the series, which ended its five-year run on NBC and DirecTV last year. Romney said in Iowa earlier this week that the phrase is "compelling." "That's Americans," he told an audience. "We have clear eyes — we know what we believe. Full hearts — we love this country and we can't lose. This is a time for Americans to make a choice. We're going to take back this country."

But the low-rated, critically acclaimed series set in a Texas town dominated by football also featured several themes that might not necessarily be approved by a Romney administration. Among them: a character (Madison Burge) goes through with an abortion late in the show's fourth season. The decision follows a one-night stand the character had with a football star (Matt Lauria), and it is the school's principal Tami Taylor (Connie Britton) who guides the student through the decision process.

Another theme explored in the series is that of military parents. A character (Zach Gilford) is raised by his ailing grandmother after his mother departs, and his military father shows little sign of caring for his son.

In the letter, Berg challenges Romney and says that invoking the phrase "falsely and inappropriately associates Friday Night Lights with the Romney/Ryan campaign."

Berg is an outspoken Barack Obama supporter, as well as a successful writer-director (Battleship, Hancock). But in an interesting twist, Buzz Bissinger, who wrote the popular book about an Odessa, Tex, high school football team that formed the basis for the movie and TV series, recently wrote that he's supporting Romney.

Email: Matthew.Belloni@thr.com

Twitter: @THRMattBelloni