WATCH: Ali Wong Surprises Best Friend Who Housed Her During Difficult Time with a Home Makeover

Ali Wong is feeling extra generous in the latest episode of Celebrity IOU.

The comedian, 40, teamed up with Property Brothers' Drew and Jonathon Scott to help renovate the basement and backyard of her best friend of 20 years, Citadelle.

The makeover, Wong says, is in part to pay back Citadelle for letting the Always Be My Maybe star crash at her and her husband Victor's newlywed home for what was meant to be two weeks — and turned into a year! — when the comedian first moved to Los Angeles.

"You've always just been so giving to me. You and Victor had just moved in together and you let me live with you guys for so long," Wong said. "I'm basically a professional moocher. And if I don't give back to you soon I will not be able to continue mooching."

Citadelle also helped Wong's family through a difficult time.

"My dad passed away and my mom was feeling really alone in San Francisco so my mom would visit L.A.," recalls Wong. "So not only did [Citadelle] have this struggling comedian/actress in her second room, she also had a senior citizen staying with her every weekend, and she didn't care. She really is like a sister to me."

Citadelle, who Ali said is not a crier, teared up after the Scott brothers surprised her with the news of the renovation.

"I can't believe this is my life. I can't believe this is happening," Citadelle said. "I honestly feel like she doesn't owe me anything. I feel like her friendship has been such a gift."

Citadelle, who Wong calls "the rock" of their friend group, is also a busy mom, keeping everything running with her husband and kids.

"The daily list of things to do for her is endless and relentless. So to be able to do this one thing that's all taken care of, where all the decisions are being made, I think is just gonna be really, really special and is really gonna give her some well-deserved relief and joy," Wong said. "I really wouldn't be where I am if it wasn't for her and this is the least I could do for someone who has given me so much."

In the exclusive clip above, viewers get to see Wong's signature playful side as she tears down fireplaces and floors with Drew and Jonathon.

The clip opens with Jonathon putting on a dramatic announcer voice: "Coming up next, we've got Ali Wong!" With a sledgehammer, Wong simultaneously screams and hit the wall of a shower. She hilariously barely makes a dent.

"It's scary, you're like an action hero. You're picking up these huge weapons basically and battling it out with this old a-- wall and these old a-- tiles," she says of the hands-on work. "They're literally glued and cemented to the floor. They're meant to stay there forever. Like that was the person's intention like it was not to be drilled up by this 5-foot lady trying to do something nice for her friend."

The reveal in Wong's episode was definitely emotional for her friend. "It feels like sunshine for the first time in a long time. I'm really appreciative of it," Citadelle said. "It's like Ali. It's a huge ray of sunshine."

"This has absolutely been one of the top four days of my life," the married mom of two jokes. "I'm just so touched that you would think of me, and it's completely exceeded anything I could have imagined. It's amazing."

WATCH THIS: The Property Brothers Embark on a New Season of Celebrity IOU With Some Amazing Celeb Guests

This season of Celebrity IOU also features Tiffany Haddish, Halle Berry, Lisa Kudrow, Anthony Anderson, Snoop Dogg, Howie Mandel and John C. Reilly.

In April, Drew talked to PEOPLE about what make the show so special.

"When we're revealing the space and you see them with their friend. It's almost like you're seeing them 20 years ago," Drew said. "They're just being real people and you see that emotional connection. You can't help but cry because it's so touching to see these celebrities in such a personal space."

New episodes of Celebrity IOU air Mondays at 9pm ET/PT on HGTV.