Martin Short wasn’t initially sure how Selena Gomez would be as a costar, but it wasn’t long at all before he learned that working with her was “fabulous” — from the “first second” they began on Only Murders in the Building.

Gomez’s inaugural Rare Impact Fund Benefit on Wednesday night, Short, 73, opened up about how Gomez, 31, was anything but the “pop princess nightmare” he feared.

“The first day we shot, I had never met Selena. Because of COVID, we’d only Zoomed,” Short recalled. “And I was driving to work and I thought, I wonder what Selena’s could be like? I mean, she could be a nightmare. She could be a pop princess nightmare.”

But, continued Short, “Right away — from the first second we started to the makeup room — it was, like, fabulous.”

He added that Gomez is “always on time, always knows her lines. So good, so talented, such a pro — it’s fabulous.”

Short, who stars as Oliver Putnam alongside Gomez and Steve Martin in the Hulu series, has since joined forces with the multi-hyphenate for three seasons of the show, which was just renewed for a fourth.

And Short made sure to support his friend at her Hollywood benefit, which Gomez hosted in an effort to raise funds for young people’s mental health. The actor, who showed up in support because “mental health is something that touches every family member,” also elaborated on the importance of someone like Gomez using her fame to make an impact.

“Well, that’s what everyone with that kind of clout should do,” he says. “When you have 440 million Instagram followers, you don’t want to just make it about your merch.”

Gomez herself also opened up at the benefit for the fund, which her 10-year-old sister Gracie inspired the creation of.

“It is my first time throwing something and I hate asking people for money, so I don’t know,” she said when asked if she wanted the Rare Impact Fund to be part of her legacy. “It’s like a weird concept, but I know that we’re doing a good thing and I couldn’t be more lucky to have the platform to do that.”

The Only Murders star also spoke about how she no longer feels pressure to reach certain achievements in her 30s.”Now that I’m 30, I care less, so it’s actually nice,” she also shared. “I get to focus on the things that actually matter and I’m not worried about things that were holding me back.”

Only Murders’ third season saw the inclusion of big names such as Meryl Streep, Jesse Williams, Ashley Park and Paul Rudd, and showrunner John Hoffman previously told The Hollywood Reporter that there is “no greater hope” than having both Williams and Streep come back for more action in season 4.

“I mean, for God’s sakes, I would bring Paul back if we can,” he added. “Listen, I would bring everyone back, and that might happen. Victims, killers, they’re all able to play in the landscape within this sort of certain narrative ways we can tell our stories.”

Only Murders in the Building can be streamed in full on Hulu.