In the fourth episode of Season 4 of This Is Us , Randall Pearson the upbeat yet neurotic, pep-talking father of three girls, played expertly by Sterling K. Brown meets a teenage boy interested in dating his daughter Deja (Lyric Ross).

Randall and his wife, Beth (Susan Kelechi Watson), recently moved their family from the New Jersey suburbs to Philadelphia for his job, so theyre trying to help their kids, including daughters Tess (Eris Baker) and Annie (Faithe Herman), adjust to a new normal. Raising a teenage daughter who has an older boyfriend is definitely uncharted ground for Randall, but hes excited to get to know Malik (Asante Blackk), a schoolmate whom Deja has been talking to for a few weeks.

That is until he finds out the 16-year-old is a father himself.

When my daughter gets old enough, I plan on installing a tracking device on her, Malik laughs while a slightly confused Randall stares down at him during their first meeting . As Malik realizes Deja didnt tell Randall about his 6-month-old daughter, Janelle, he explains that he has full custody and occasional child care support from his parents.

For Lyric Ross, playing out this complicated plot point is a thrill, albeit a surprising one. I didnt really know how much more they could do with this character, Ross, who is 16 herself, told HuffPost. She was a foster kid, adopted as part of the family I didnt know they could take it even further with a whole different storyline.

Its not easy to portray someone whos trying to overcome a tragic past, but Ross said the loyal This Is Us audience keeps her eager to bring Dejas story to life. The character has really resonated with the shows viewers, whether theyre personally familiar with the foster care system or not.

They see all of this hurt that this girls feeling, Ross said.

Deja was introduced in Season 2. Viewers learned that her mother had her when she was 16 and struggled to raise Deja alone following her grandmothers death. After the little girl was hospitalized with a bad cut to the hand, Child Protective Services noticed some inconsistencies in Dejas home life and put her in the foster care system. She rotated through a few homes some abusive, some over-crowded before she was reunited with her mother. But then her mom was arrested for possession of an unlicensed gun. Thats when a 12-year-old Deja was placed with Randall and Beth, who eventually became her permanent guardians when her mother realized they could provide her daughter with a more stable life.

At first defiant, Deja comes to love the Pearsons and forms a beautiful bond with Randall, who was adopted himself by Rebecca (Mandy Moore) and Jack Pearson (Milo Ventimiglia) after one of their triplets died during childbirth.

Ross, joined by her mom, Brandi, talked to HuffPost about her journey as Deja and what it means to play a Black foster kid on primetime TV.