During a panel discussion in anticipation of the premiere of the second batch of episodes, Kidman — who plays Celeste on the HBO drama series — was asked what it was like to work with Alexander Skarsgard in Season 1.
Kidman's response caught the attention of audience members, PEOPLE writes, but it was co-star and executive producer Reese Witherspoon's reaction to the answer that reveals she just dropped a big spoiler for the second season.
"He was the most incredible acting partner, and then he came back for season 2," Kidman said Wednesday during the event hosted by The Wing Soho, a work and community space designed for women.
Witherspoon giggled, but reportedly seemed concerned as she motioned to her co-star to stop talking. Kidman realized what she had done and attempted to take back her comments.
"He has a little bit of a part in the sense of... the basis of... okay, I'll be quiet," Kidman said. "He didn't abandon us. We'll put it that way."
The Season 1 finale of the HBO series ended with the Monterey 5, played by Kidman, Witherspoon, Zoe Kravitz, Shailene Woodley and Laura Dern, getting into an altercation with Perry (Skarsgard), ending with him being pushed down a flight of stairs to his death.
Since the announcement of Season 2, fans have speculated if Skarsgard's character would return for the new episodes, where it through flashbacks or a last-minute twist.
Skarsgard attended the Season 2 premiere event but stayed mum on whether or not he would return for more episodes.
"I'm just here for the free alcohol and snacks," Skarsgard told Variety Wednesday night. "I'm very dead... unless I come back as a zombie. He was pretty badly impaled. I'm afraid he did not survive that."
When reminded he could show up in a flashback scene, Skarsgard coyly replied, "So I've heard. Yeah... I don't know, we'll see."
At the time, the actor also revealed he had read the scripts for the new episodes.
"[I'm] very excited for people to see it. They way [Streep] comes in to the dynamic of the group, asking some hard questions. It creates a lot of tension. There's great drama in that, so I'm excited to see it," he told the outlet on the red carpet.
The Season 2 trailer gave a look at what is ahead for the women of Monterey, including the introduction of Meryl Streep's character. She is set to play Mary Louise Wright, Perry's mother determined to find out what happened that night.