Kristen Sewart has gained immense weight in the recent days and it has led to rumors that the Twilight stars might be pregnant with Pattinson's baby. Stewart was recently spotted with looking a bit heavier, with approximately 15 pounds weight gain and this made the Robsten fans believe that Stewart could be expecting a baby. However, the rumors were put to rest by Hollywood dietician Lisa DeFazio who revealed that Pattinson has gained weight for a movie role and it has nothing to do with the pregnancy.

Lisa DeFazio told Hollywoodlife, "She (Kristen) definitely has gained weight, however, it is not a bad thing! She was getting to be too thin anyway, and now it appears she is eating, looks healthy, happy and has some curves."

A friend of Stewart's further revealed, "Kristen is absolutely not pregnant. She has put on a few extra pounds for a movie role and that's it. She's already so thin so a few more pounds makes a noticeable difference, she's still thin."

Stewart is working hard for her role in the new movie "Still Alice" and regarding her sudden weight gain De Fazio said that there is no unhealthy eating involved. Reportedly, Stewart is not munching on cookies and cholesterol-laden food. On the contrary she has increased her protein intake.

"The healthy way to gain weight is by eating lean protein like fish, chicken and beans, drinking high calorie weight gain protein shakes, including carbohydrates like rice and pasta, and fruits and vegetables, " revealed the dietician

Stewart's pregnancy rumors swirled after multiple sources reported she spent Valentine's Day with Pattinson.

"Even though [Rob] and Kristen aren't together, he wanted to make sure that she knows she still matters to him," an insider told Hollywood Life, adding, "Rob is good with stuff like that.

Meanwhile, Pattinson is being linked to long time friend Katy Perry . Perry is leaning on Pattinson for emotional support since she called it quits with long time beau Jason Mayor.