Mary-Kate and Ashley Olsen were inescapable in the '90s and early 2000s, and their sister Elizabeth Olsen is a bona fide Marvel Cinematic Universe star as Wanda Maximoff, a.k.a. Scarlet Witch. However, did you know that there is a fourth Olsen sister?

Born in 1996, Courtney Taylor Olsen is the half-sister of Mary-Kate, Ashley and Elizabeth Olsen. All of them share the same father, David Olsen. However, Courtney's mom is David's second wife, McKenzie Olsen.

According to The Richest, Courtney has starred in two movies: 2014's Malignant Spirits: Sense of Fiction and 2015's YOLO: The Movie. She doesn't appear to have starred in any other film or television roles since.

Unlike her more famous sisters over the years, Courtney leads a private life out of the spotlight. She hasn't done many interviews and details about her are relatively scarce.

However, every now and then she will share little details of her life via Instagram. Case in point: She appears to have a good relationship with her sisters.

In one Instagram post from 2018, she can be seen posting next to a poster for Avengers: Infinity War, starring her sister Elizabeth.

"Just admiring my badass of a sister," she captioned the post.

She also reportedly went to the premiere for Doctor Strange in the Multiverse of Madness to support her sister.

Despite her staying out of the spotlight, Courtney does seem to have some Hollywood connections in her personal life. In fact, one of her best friends appears to be former child star Madison Pettis, who played Sophie Martinez on the Disney Channel original series Cory in the House, according to IMDb.

Though she seems to have chosen to remain out of the spotlight for now, the fourth Olsen sister could very likely see her sisters' support should she return to the entertainment business.

Celebrity Siblings Who've Co-Starred On-Screen