Next week’s four-way crossover event between “Arrow,” “The Flash,” “Supergirl,” and “Legends of Tomorrow” will remind viewers of Melissa Benoist’s “Glee” roots.

According to TV Guide, Benoist’s Kara, aka the Girl of Steel, will sing at Barry (Grant Gustin) and Iris’ (Candice Patton) wedding. While the song she’ll be singing is being kept under wraps, the news outlet teased that fans won’t be prepared for how awesome her performance is.

But aside from being the wedding singer at Barry and Iris’ nuptial, viewers can expect a lot more things from Benoist in the crossover. As seen in the official trailer and promo photos for the TV event, the actress plays both Supergirl and Overgirl in the crossover. While playing a new character is always exciting for Benoist, the actress admitted that doing double duty in the crossover was a challenge.

“I did play two characters. I did wear a very different outfit. There’s still a cape and my face is covered and she’s not so nice. It was pretty challenging,” the actress told ComicBook.com and other news outlets during a recent press visit to the Vancouver set of “Supergirl.”

Although Benoist already played two different characters simultaneously in a couple of “Supergirl” episodes before, she said that portraying Supergirl and Overgirl in the crossover was a different experience. “I’ve had moments like [this] on this show [‘Supergirl’] with Bizarro and when Martian Manhunter (David Harewood) takes over Kara’s body, but this was entirely different. This was not even Red Kryptonite-isque. This was way worse.”

Benoist said that playing Supergirl and Overgirl was particularly difficult when they did motion control shots where she had to be in the scene with herself. “It’s more tedious than a traditional split screen,” Benoist said. “And essentially, you’re memorizing a whole scene, every line, every bit of dialogue and I didn’t anticipate how hard the transition would be to go from lightness to darkness. [It’s] a fun challenge.”

The crossover, titled “Crisis on Earth-X,” airs across two nights. It begins with “Supergirl” and “Arrow” on Monday, Nov. 27 at 8 p.m. EST, and ends with “The Flash” and “Legends of Tomorrow” on Tuesday, Nov. 28 at 8 p.m. on The CW.