Lexie first appeared on Grey's Anatomy at the tail end of Season 3, joining the cast full-time in Season 4. Her first day as a surgical intern at Seattle Grace also revealed that she was in fact Meredith's sister, though the two didn't have much of a relationship to speak of beyond their genetic ties. At first, many fans of the show couldn't find reasons to love her. But time, and her iconic relationship with plastic surgeon Mark Sloan, brought many around to her unique character.

Because Lexie was absent for a portion of Season 8, some initially suspected that she was being written out of the show long before it happened. Though rumors of behind-the-scenes drama always accompany an actor's departure from a series -- especially when said actor's character dies -- Leigh was very open about her reasons for leaving, which likely further solidified her decision to make a brief return in Season 17.

The "Grey" in the hospital's rebranded name Grey Sloan Memorial actually refers to Lexie, as well as Mark Sloan, who were both victims of the plane crash from Season 8. Lexie's death caused emotional turmoil across the Grey's fandom, even among those who didn't like her character in the beginning. Immediately, fans wanted to know the reason Leigh was presumably leaving the show for good.

Leigh actually made the decision to leave on her own, telling TV Line at the time: "Earlier this year, I made the decision that Season 8 would be my last.

I met with Shonda [Rhimes] and we worked together to give Lexie's story appropriate closure."

The end of her full-time gig as Lexie Grey wasn't the end of her acting career, however. Since leaving Grey's Anatomy, Leigh has gone on to play Alex Danvers in both Supergirl and The Flash. In 2020, however, fans were met with a handful of surprise return guests including Leigh's very own Lexie.

Meredith Grey spent the majority of Season 17 in a coma.

To further develop her character and to give her the opportunity to say proper goodbyes to multiple people from her past, the show created a beach setting within her subconscious state where she could move around and interact with characters who were otherwise long dead. Lexie's return on Meredith's "coma beach" wasn't just meaningful to fans -- it also meant a lot to the actors making their return appearances, Leigh included.

"It was a really interesting experience just because I did have to film it up here in Canada because you can't travel back and forth," she told People. "But understanding there are dynamics between Lexie and Meredith, and then Lexie and Mark …To be part of that was obviously very special. And to be able to close the chapter for Lexie... It was a special experience to be able to be part of that."

New episodes of Grey's Anatomy premiere Thursdays at 9 PM ET on ABC and can be streamed the following day on Hulu.