Kristen Stewart isn't known for her cheery smile in paparazzi shots, as the star is notorious for her dislike of being publicly photographed, but recent pictures of the actress reveal some shocking hair loss that friends claim may be due to stress over losing Robert Pattinson, the Daily Mail reports.

The 23-year old actress was recently photographed in Berlin, Germany, where she is currently filming her new movie, "Sils Maria," wearing her long brown hair swept back to the side, noticeably bald in some spots. Hair loss is often a symptom of severe stress, and insiders recently told Now magazine that there is widespread concern over the star in her circles, as her friends reportedly believe she needs a break as she is becomingly increasingly overwhelmed after losing her "Twilight" beau Robert Pattinson earlier this year.

"Kristen's circle are so concerned about her that two of her friends have flown to Germany to see her," an insider told Now. "They want to take her to a de-stressing yoga retreat on the outskirts of Berlin. They've also begged Rob to visit her on set. They fear the stress is getting worse because she's been trying to make contact with him and he's ignoring all of her calls."

While conflicting reports over the past month have claimed that Stewart and Pattinson are likely getting back together, it looks as though that may not happen as soon as fans were hoping, if at all. However, all reports on Stewart seem to confirm that the actress has been badly missing her ex-boyfriend, who broke things off with her for good this spring, allegedly because he could no longer trust her in the wake of her highly publicized affair with her then-married film director, Rupert Sanders.

Though the two have remained friends and Pattinson has even visited Stewart's home in Los Feliz, Calif., it seems as though Pattinson may not be so privvy to the reunion that Stewart has been planning over the past few months. This has taken quite a toll on the star, especially where her hair is concerned. The actress has been seen wearing extensions to cover up her hair loss while on the set of her new movie.

"It appears Kristen has telogen effluvium," hair expert Gary Heron from The Hair Centre in Westminster said to the Daily Mail. "This means the growth of hair is interrupted prematurely and the growth cycle isn't as it should be. Her hair is very thin and the loss looks extensive. Kristen is far too young for this not to be have caused by stress. To remedy the situation, Kristen needs to change her lifestyle. She should start eating a balanced diet, which will assist regrowth, and take better care of her hair."

Click here to see photos of Kristen Stewart's troublesome hair loss that was captured while paparazzi photographed her in Berlin, on the set of her new movie.