In the video, Jessica, 29, stood closely next to Cody, 35, in the backyard of their home as he shot off a confetti cannon and pink paint and confetti filled the air, revealing the couple has another baby girl on the way.
"It's a girl!!!" flashed across the screen as Jessica and Cody hugged each other and celebrated.
Although Cody was smiling, he appeared slightly underwhelmed they're not having a son considering he's already a father to two girls -- Maverick, 13 months, whom he welcomed with Jessica and Paisley, 8, from a previous relationship.
Jessica therefore teased Cody and playfully slapped him with the cannon, assuring the camera, "I'm happy!"
Big Brother alum Elena Davies filmed the gender reveal for Jessica and Cody, who fell in love on Season 19 of Big Brother in 2017 and then got engaged on February 13, 2018 shortly after winning the $1 million prize on The Amazing Race's 30th season.
"Cody is good at making girls!" Elena joked from behind the camera.
Jessica admitted in her Instagram Stories on Tuesday that she accidentally spilled her baby's gender with a pronoun when talking to fans on her page and so she and Cody decided to post their gender reveal on YouTube a bit earlier than anticipated.
On Mother's Day, Jessica posted a family photo on Instagram and captioned it, "I love them. Plain and simple... Super happy to announce that not only do we know @babynickson gender but we also have a name picked out."
"It's nice to be able to call this squirmy little one by a name."
Jessica is four months into her pregnancy, and the new baby is due in October 2020.
"Since we have to schedule our csection still, we don't have an exact date but hopefully this delivery will be much more smooth!" Jessica wrote on Instagram over the weekend.
"But I'm very excited because October is my favorite time of year and I can also celebrate my 30th with the whole family come December."
"FINALLY! As you guys know, Cody and I have been wanting to have all our kids pretty close in age so we were determined to get pregnant this year," Jessica wrote last week.
"A part of me wanted to straight Kylie Jenner it and tell you guys after the birth but after several accidental IG stories with our ultrasound peaking through in the background, we knew it was time to come clean."
"Maverick is going to be a big sister! I'm not really sure if she fully understands that yet but no matter what, she's always going to be my baby."
Jessica did not debut her first baby bump until December 2018 when she was 22 weeks along with Maverick in order to avoid haters and trolls, but this time around, Jessica doesn't appear to be shy or holding back.
For example, Jessica recently posted a baby-bump photo in a blue dress with white polka dots.