According to People magazine, Ross, 34, who also starred in the film, filed for divorce Friday from her estranged husband, Sanders, 41, in Los Angeles County Superior Court on Friday.
Ross and Sanders have been married for 10 years and have two children, Skyla, 7, and Tennyson, 5.
Us Weekly reported that she is seeking joint custody of the kids, spousal support and attorney's fees.
Ross' rep did not immediately respond to ABCNews.com's request for comment.
It's been about six months since Sanders publicly apologized for the affair following Stewart's surprising public admission that she cheated on then boyfriend and "Twilight" co-star Robert Pattinson.
"I am utterly distraught about the pain I have caused my family," Sanders said in a statement to People in July 2012. "My beautiful wife and heavenly children are all I have in this world. I love them with all my heart. I am praying that we can get through this together."
Stewart appears to have patched things up with Pattinson, but despite what appeared to be attempts by Sanders and Ross to reconcile, the estranged couple could not.
Ross had hinted at changes to come in a video series for Alexander Wang after walking in the designer's New York City fashion show last fall: "[This year was] the end of some things and the beginning of something else," she said. "Beginnings and endings are always really exciting."