Why Ellie Olstern From Chicago P.D. Looks So Familiar

Showrunner and executive producer Dick Wolf should be a familiar name to fans of police procedurals, as the mastermind behind the classic series "Law & Order" and its numerous spin-offs, including "Law & Order: Special Victims Unit." The magic touch of Wolf, however, is just as evident in the "One Chicago" franchise on NBC, which includes the police procedural "Chicago P.D.," which has drawn both fans of police procedurals and fans of the larger franchise, which includes "Chicago Fire" and "Chicago Med."

A particular episode in Season 4 made a big impact on "Chicago P.D." fans. Titled "I Remember Her Now," the episode focused on the investigation of a treatment center for troubled teenage girls following the death of a 15 year old girl who had run away from the place. One of the episode's guest characters, Ellie Olstern, stood out in particular, leaving many viewers wondering if and where they had seen her before. 

The performer's name is Danika Yarosh, and this is why she looks so familiar.

Danika Yarosh began her career with a number of guest roles in prominent shows such as "30 Rock." However, it was in the Showtime series "Shameless," an adaptation of a UK series of the same name, that she first made a more substantial mark on many viewers.

Yarosh made her first appearance in the Season 4 premiere of the series, titled "Simple Pleasures," as the older version of Holly Herkimer, a character first introduced in the show's second season, played then by Dove Cameron. In the fourth season, Holly is still friends with Debbie Gallagher, played by Emma Kenney, and acts as Debbie's guide into sexuality. Among other things, Holly tells Debbie to initiate sex with her boyfriend, then expresses surprise when Debbie tells her she was rebuffed. Holly and Debbie also get into internet prostitution, selling their virginity online.

In Season 5, Debbie is shown as having come into her own sexually, and Debbie and Holly remain friends in Season 5, but ultimately get into a fight that escalates into a physical altercation and destroys their friendship. The fight ended Holly's (and by extension, Yarosh's) time on the show.

Danika Yarosh's next major role came in the NBC superhero drama "Heroes Reborn," a continuation of the cult-favorite series "Heroes." In the show, Yarosh plays Claire Bennet, the daughter of Claire Bennet, who was played on "Heroes" by Hayden Panettiere. Malina is one of a pair of twins, and her twin brother, named Tommy Clark, is played by Robbie Kay. The duo are transported to 1999 following their birth, during which Claire dies — to protect them from Renautas and its CEO, Erica Kravid (Rya Kihlstedt). They are separated, after the discovery that Tommy has the ability to absorb powers.

Malina discovers that she is meant to use her power of being able to control to elements to stop an extinction level event called H.E.L.E., and she trains her entire life for it. When her mentor and trainer is captured by Renautus, Malina sets out to find Tommy with the help of Luke Collins, a fellow mutant who can control solar energy and is played by Zachary Levi. Over the course of the search, she is united with her adoptive grandfather Noah Bennet, a role Jack Coleman reprises from "Heroes."

The duo eventually do find Tommy, and as H.E.L.E hits Earth, the two join forces with Noah to try and stop it. They successfully manage, but Noah dies in the process, and the series ends with Malina attending Claire's alma mater, Union Wells high school. She finds a tarot card in her locker, which her great grandmother says is a sign that the twins' father is back in town.

Television wasn't the only place where Danika Yarosh made an impact, as she also appeared in the 2016 action thriller sequel "Jack Reacher: Never Go Back," starring alongside Tom Cruise and Cobie Smulders.

In the film, Yarosh plays Samantha, a 15-year-old who may be the biological daughter of Jack Reacher, played by Cruise. When Reacher and Susan Turner (Cobie Smulders) look into who is framing Reacher for a number of murders, they discover that Samantha is being watched, and rescue her after finding her adopted parents dead. The three go on the run together, with Reacher and Turner forcing Samantha to abandon her phone once they discover she has it (and can, as a result, be tracked by it).

Samantha admits to Reacher that she filed the paternity suit that alerted Reacher to her existence, and unwittingly alerts the group after them to their location after using a stolen credit card. Samantha ends up captured on a rooftop, but Reacher kills her assailant, and she escapes.

Samantha subsequently runs a test that reveals that Reacher is not her father, as he doesn't recognize her biological mother, nor does she recognize him. Nonetheless, she secretly gives Reacher a cell phone so the two can remain in touch.

Danika Yarosh moved back to television for her next major role, appearing in the second and final season of the USA Network horror series "The Purge." The series, which is a spin-off of the movie franchise of the same name, sees Yarosh appear as Kelen Stewart, a student at Cooke University and the girlfriend of Ben Gardner (Joel Allen).

Ben gets trapped while out on one purge night and is forced to kill his assailant. He subsequently returns to the site and picks up the assailant's mask, which has "God" written across the forehead. While Kelen keeps checking in with Ben and he keeps insisting he's fine, he discovers that his Purge night encounter gave him a thirst to kill. He wears the mask when he kills another student, which causes an upheaval on campus due to being a murder outside of Purge night, and the picture of Ben wearing the mask from surveillance camera footage is shown on the news.

On a trip home, Kelen looks through Ben's luggage and is horrified to discover the mask. Ben realizes she knows his secret, so he pursues her ... and in the process of running away from Ben, Kelen is hit by a car and dies.

Danika Yarosh followed up her work on "The Purge" by once again taking on an existing character in an ongoing series, much like she had with "Shameless." This time, Yarosh jumped into the role of Brooke Osmond in the third season of the Netflix series "Greenhouse Academy," taking over from Grace Van Dien, who played the character in the first two seasons.

Brooke is the daughter of Louis Osmond (Parker Stevenson), who is the headmaster of The Greenhouse until his son's arrest. In Season 3, Brooke struggles with her father losing his position, as well as her brother's arrest and subsequent breakout from prison. Brooke hides her brother, Jason (Yiftach Mizrahi) after his escape, but her then-boyfriend Alex Woods (Finn Roberts) discovers Jason and gives him the option to either leave or be reported to the authorities. Brooke ultimately breaks up with Alex in the midst of a basketball game he is participating in, and subsequently switches from her existing group of The Eagles to another group, The Ravens.

In Season 4, Brooke begins to look more into the secrets that Jason harbored, and she tries to repair her platonic relationship with Alex. She also works with the others to discover the root of the mysterious illness afflicting Leo Cruz (Dallas Hart), the captain of The Ravens who suddenly gets sick and needs a bone marrow transfusion to survive. Brooke eventually rejoins The Eagles and rekindles her romantic relationship with Alex.