Mayim Bialik Sheds a Tear While Surprising Her 'Incredible' Friend of 18 Years with a Backyard Makeover (Exclusive)

The ‘Big Bang Theory’ alum teamed up with Drew and Jonathan Scott to transform her longtime friend Nancy’s outdoor space on 'Celebrity IOU'

Mayim Bialik is giving back to her best friend of 18 years who has always been by her side.

PEOPLE got an exclusive first look, above, at Monday's all-new episode of Celebrity IOU, in which the Big Bang Theory actress, 48, teams up with Drew and Jonathan Scott to surprise her longtime friend, Nancy, with the ultimate backyard transformation.

“Nancy is my sister from another mister,” Bialik tells the brothers. “I’ve gone through some really hard times and hard transitions. I’m a work-in-progress, but there’s no one who stuck it out with me like Nancy has.”

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While Nancy visits her hometown in the Midwest, Bialik and the brothers work hard to transform her barren backyard into a lush oasis equipped with a firepit, outdoor kitchen, private yoga studio where Nancy can get some quiet time away from her kids.

The studio is a little nod to the beginning of the pair’s friendship, Bialik reveals, as they first met at a prenatal yoga class nearly two decades ago. The star has two sons, Miles and Frederick, whom she shares with ex-husband Michael Stone.

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In the exclusive clip, the former Jeopardy! host rolls up her sleeves to take out some weeds and begin the demolition process.

“Amazing, we’re already making things happen,” Jonathan says. Bialik adds that she’s a bit nervous they won’t be able to get the project done before Nancy returns from her trip in three weeks.

“I definitely have a little bit of anxiety — excited anxiety — about the timing,” Bialik explains. “I’m trying to squeeze this in and I really want it to be a surprise for her.”

She adds, “Creating a little bit of zen in her yard seems like a really beautiful way to show how much I care for her and love her.”

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In the tearjerking final reveal, the actress explains to her best friend why she deserves to have a space of her own after Drew and Jonathan Scott come out from the trees to surprise her.

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“So Nancy, I went to these fine gentlemen and said I have a friend who’s the most important person in my life and the best friend I could ask for. You work your butt off for everyone else and you’re an incredible person.

With tears in her eyes, Nancy responds, “I am speechless.”

Celebrity IOU airs on HGTV every Monday at 8 p.m. ET.

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