According to the Hollywood Reporter, Biel will play "the hottest scientist in the world" in an episode for the comedy's upcoming fourth season.
Her character will go head-to-head with Zooey Deschanel's character Jess Day as they both set their sights on the same man at a wedding.
The upcoming season of "New Girl" premieres on Tuesday, Sept. 16. Biel's TV resume includes seven seasons on "7th Heaven."
Biel has starred in films including "The A-Team," "Total Recall" and "New Year's Eve."