To achieve the physical look of former professional road racing cyclist Lance Armstrong, actor Ben Foster apparently underwent what sounds like a grueling restrictive diet. 

"House of Cards" actress Robin Wright, who recently became engaged to the actor, told OK! Magazine that she joined Foster on the diet out of solidarity. 

"My fiance did a movie recently, playing Lance Armstrong, and he was on an 800-calories-a-day diet. I said, 'In solidarity, I am going to go on the diet with you,' even though I really want to go to an In-N-Out Burger," she said.

Foster follows in the footsteps of other actors who have taken extreme means to get into character — including Matthew McConaughey, Jared Leto and Anne Hathaway. Unlike these stars, however, Foster has to both capture the look and the power of someone capable of winning the grueling Tour de France seven times. 

The film, directed by Stephen Frears, is based on Irish sports journalist David Walsh's book, "Seven Deadly Sins: My Pursuit of Lance Armstrong." It will reportedly cover Armstrong's battle with testicular cancer, his cycling comeback, Tour de France victories, and finally, his fall from grace after a massive doping scandal. Foster's film is one of several currently in development about the disgraced cyclist. 

Related on MNN: How Matthew McConaughey used pudding to achieve 'Dallas Buyers Club' weight loss

Michael d'Estries ( @michaeldestries ) covers science, technology, art, and the beautiful, unusual corners of our incredible world.

Ben Foster's restrictive 'Lance Armstrong' diet
Robin Wright says her fiance was on an 800-calorie-per-day diet to get in shape for the sports biopic.