On season 3 of Party Down, Jennifer Garner is a welcome addition to the cast of the Starz comedy as Evie, a film producer who falls for Henry (Adam Scott) and starts spending more and more time with him while he spends time working for the titular catering company. By episode four, “KSGY-95 Prizewinner’s Luau,” which debuted on Friday, their relationship is in full swing when the two decide to spend his latest shift working a pre-concert Malibu luau on mushrooms. 

But they’re not the only ones who decide to take the hallucinogenic, with the rest of the team — played by Martin Starr, Ryan Hansen, Tyrel Jackson Williams and Zoë Chao — joining in on the hilariously unexpected adventures that follow, especially for Garner’s character, whose emotional ups and downs allow the 50-year-old actress’ comedic chops to really shine. 

“It was terrifying,” Garner tells ET’s Will Marfuggi about learning what she had to do in the episode. “Any time I have to play inebriated or any altering anything to me, I don’t have a lot of experience but Ken Marino really held my hand and he was amazing director.”

She adds, “He really made me feel good as one can feel when they are standing on their head.” 

“It was a fun episode to direct, for sure,” Marino, who returns as the catering team’s struggling boss, Ron, says about helming the episode, while the rest of the cast dishes on Garner’s performance. 

When it comes to Evie’s journey in the episode, she not only struggles to act as Sackson’s (Williams) spiritual guide while he experiences his first high on mushrooms but she also spends time reflecting on where she’s at in her career and what she should do next. “When I was starting out, I really thought I was going to make important independent cinema,” Evie says about the fact that she has to pitch projects like Douglas Fir, about a man who is part tree, and its spinoff, Manputer, about a character that is part man and part computer. 

She then realizes she’s lost track of Sackson, which sends her off on a hunt for her newfound friend. “I lost Sackson,” she says before spending the rest of the episode trying to find him via his livestream. 

“It was so much fun and so hilarious and awesome to see Jennifer Garner on ‘shrooms,” Williams says. “It was very comforting to be like, ‘Oh, OK. Great, like, I’m not the only, we’re not the only people, like, hitting the gas on silly.”  

“She played it perfectly,” Hansen adds, before Starr jokes that she had “mushrooms in her system, at all times.” The actor then deadpans, “Some people microdose and she macrodosed.” 

But on a more genuine note, Garner’s new co-stars had nothing but kind things to say about her not only joining the ensemble, but how well she fit in despite not necessarily being known for starring in these types of comedic projects. “She’s so fun to work with and so sweet,” Starr says. “I really didn’t expect her to get our tone of humor the way that she does, but she nails it on and off camera. She fits right in, and is so sweet.”

“She was game from word one. She was hilarious and great, and I think stepping into any show where everybody knows each other — and you know, I used to make my living doing guest spots on TV shows. It’s always intimidating, and you feel like the new kid in school — but we make a real effort on Party Down for guest actors not to feel that way,” Scott says, noting that here “she was a series regular on the show and so she just jumped in.”

While Scott says they did what they could to make her feel welcome, “she needed zero help. She was just, you know, excellent and hilarious from day one.”

“Yeah, she’s a freakin’ pro. I mean, she’s been around for so long and she gets the comedy in all that stuff. She was incredible and so game,” Hansen says, admitting to having “a small crush” on Garner. “She’s incredible. She’s one of the coolest people.” 

Of course, Garner wasn’t the only newcomer this season, with her being joined by Chao and Williams, resulting in their own little bond within the entire group. “I mean, we clung to each other,” says Chao, who plays the team’s chef named Lucy, before reflecting on watching season 3. “I watched five out of six episodes and she is so charming and so likable — and just like a real movie star… I just fell in love with her again because she is one of the loveliest people I’ve met.” 

She adds, “I ran into her recently and she was like, ‘Did we shoot that? Did we shoot Party Down season 3? Are we in it? Was that real?’ And I understood what she was feeling because it sort of felt like it was a dream and we weren’t ever sure if we were doing a good job or had, you know, gotten the pitch right. But I’m excited for her to be relieved when she watches it.” 

And that’s a good thing considering that Scott recalls that when it came to casting Evie, they really wanted a Jennifer Garner type. “I still can’t believe Jennifer Garner actually did the show,” he says, explaining that they wanted “someone like Jennifer Garner [but we were like], ‘We’re not going to get Jennifer Garner…’ So the fact that we actually got Jennifer Garner is bonkers.” 

But in the end, it worked out. “She was game for anything and you have to be. So, she didn’t hold back and do the star thing like, ‘Oh, I don’t do those things.’ She was like, ‘Yeah, bring it on,'” says Jane Lynch, who reprises her role as Constance, a former actress who has since taken over Ron’s catering company.   

While everyone had a great time working with her, the episode at least provided an answer to one question no one thought would ever be addressed, with Lynch quipping, “I’ve always wanted to know what Jennifer Garner does on mushrooms.”

“Oh my gosh, same. Same actually,” Garner adds in response. And thanks to Party Down, now we can imagine it.  

Party Down season 3 airs Fridays at 9 p.m. ET/PT on Starz and is available to stream at midnight the same day on the Starz app.