PARK CITY, Utah (January 24, 2013)-- Amanda Seyfried delived deep into her role as '70s porn star Linda Lovelace in the biopic "Lovelace," which premiered this week at the Sundance Film Festival.

Seyfried, 27, said she was only able to shed the dark role by playing Cosette in the Oscar-nominated "Les Miserables."

She said she was grateful the musical part came just three weeks after "Lovelace" wrapped.

If not, Seyfried says she would have "carried Linda for a long time, and it could have been unhealthy."

"Lovelace" is directed by Oscar-winning documentarian Rob Epstein and Jeffrey Friedman and was based in part on her memoir.

The film hasn't yet been acquired at the annual independent-film showcase, so no theatrical release date is scheduled.