The tension between Lillian Luthor (Brenda Strong) and her foster daughter, Lena Luthor (Katie Douglas), is going to get even worse in Season 2, episode 8 of “Supergirl.”

In an interview with The Hollywood Reporter, Strong revealed that Lillian and Lena’s grudges for each other will surface in the episode, where Lena also happens to discover her mom’s connection to CADMUS. “Lillian and Lena have been operating in their relationship at a slow simmer this entire time and the gas just got turned up, so whatever is boiling underneath, it’s going to come to the surface in the next episode,” Strong said. “You’re going to see … explosiveness between the two of them.”

Given what Superman (Tyler Hoechlin) did to her son Lex Luthor, Lillian wasn’t thrilled when she found out at the end of Season 2, episode 5, titled “Crossfire,” that her daughter is friends with Supergirl.

“She’s never been happy about any of her children being close to Supergirl or Superman since it will only end badly,” Strong said of the Luthor matriarch. “She definitely will feel betrayed [by Lena working with Supergirl] and there’s going to be major emotional aftermath from that.”

The fact that Lena is not Lillian’s biological child also adds more drama to their relationship. “I think any mother with a daughter can tell you [that] it’s complex,” Strong told Entertainment Weekly when asked to describe Lillian and Lena’s relationship. “But there’s the added layer of Lena being adopted, and I think there is definitely a strain because Lena doesn’t feel that she is prioritized and she feels Lex was [her mother’s] favorite.”

“Supergirl” Season 2, episode 8, titled “Medusa,” airs on Monday, Nov. 28 at 8 p.m. EST on The CW. Check out the full synopsis for the episode below:

“Eliza (Helen Slater) comes to town to celebrate Thanksgiving with her daughters. Alex (Chyler Leigh) decides it’s time to come out to her mother; Kara (Benoist) is shocked when Eliza suggests Mon-El (Chris Wood) has feelings for her, and Winn (Jeremy Jordan) and James (Mehcad Brooks) consider telling Kara the truth about the Guardian. Meanwhile, CADMUS unleashes a virus that instantly kills any alien in the vicinity so Kara enlists an unexpected ally – Lena Luthor. Barry Allen (Grant Gustin) and Cisco Ramon (Carlos Valdes) seek Kara’s help with an alien invasion on their Earth.”

Katie McGrath as Lena Luthor “Supergirl” star Brenda Strong revealed that Lillian Luthor and Lena Luthor’s (Katie McGrath) grudges for each other will surface in Season 2, episode 8, where the L-Corp CEO also happens to discover her mom’s connection to CADMUS. Photo: The CW