Cooper’s Harry embarked on a new journey during the ABC drama’s Thursday, Jan. 22 episode

Warning: The post contains spoilers for Thursday, Jan. 22’s episode of 9-1-1.

The 118 has officially welcomed its newest member to the team.

On the Thursday, Jan. 22 episode of 9-1-1, “Fighting Back,” Athena’s son Harry (Elijah M. Cooper) completed his training and became a firefighter, just like his late stepfather Bobby (Peter Krause). The poignant episode culminated with an unforgettable mother-son moment, which saw Athena (Angela Bassett) pin Harry’s badge on his uniform.

In an interview with PEOPLE, Cooper, 20, opened up about filming the emotional moment with his TV mom, Bassett.

“That was a really awesome moment,” Cooper shares. “You know what? I know it’s a show, but it really made me think of my past three seasons here and everything coming together and my journey of meeting her on my first episode, really meeting everyone and just figuring out this whole journey and getting to this point.”

He adds, “I feel like it was a joyous moment. It was a moment where I was like, ‘Wow, this is really happening. This is a real smile. I’m really excited to start in this.’ “

Filming the moment alongside Bassett, 67, made it all the more special. The actor and The Aftermath Show podcast cohost says he “had a lot of nerves coming into acting with her” when he first joined the show in season 7, but the Hollywood icon quickly put him at ease.

“Literally from day one, she just had this really warm energy about her,” Cooper shares. “She had this mom type vibe. I felt good. I felt safe. I felt comforted with her.”

That feeling has only grown over the past three seasons. “I think as time goes on, you’re able to understand somebody more, feel them out, really deepen your relationship, and that’s what has happened with us too,” he continues. “And now she’s just like, she’s my second mom … we talk about all the things in life and just have a good time. So yeah, I mean, I literally call her momma.”

Now that Harry has joined the 118, he’s also following in Bobby’s footsteps, and Cooper says both he and his character felt the weight of not having the young firefighter’s stepfather there for such a pivotal moment in his journey.

Cooper explains, “I think this whole season has… We’ve had reminders of him [Bobby] constantly. And I feel like, honestly, that is what has allowed this season to be so beautiful. We’re finding a way to move on. We’re finding a way to continue to grow and remember him. Harry joining the 118 is now a remembrance of his stepfather. This is a big thing.”

“And so I think just as Harry probably was a little bit sad to have this happen, but also happy being like, ‘I’m here, I’m doing this. I really worked hard to make this all come to fruition.’ I think Elijah had that same kind of feeling when it came to Peter. So yeah, I’m just really, really grateful for all of this and continuing to every day when I show up, remember him.”

For Harry, completing his training and receiving his firehouse assignment is just the beginning. Cooper teases there’s lots more to come for his character as season 9 continues.

“Without giving away too much, I think we’re going to see Harry’s journey figuring out who he is and how he moves forward now finally being a part of the 118,” he says. “We’re going to see him go through the ups and downs of this fear that he’s feeling, but also the excitement of finally having this all come true. It’s going to be a really cool roller coaster.”

New episodes of 9-1-1 air Thursdays at 8 p.m. ET on ABC. Episodes stream the next day on Hulu and Hulu on Disney+.