On the season finale, the 28-year-old expectant mother decided to shut down all the haters and dispel rumors that she'd cheated on her fiance once and for all by taking a paternity test.
However, in an effort to spare Rob's feelings and keep the admittedly insecure 29-year-old sock designer from any stress or paranoia about her fidelity, Chyna teamed up with Rob's sister, Kim Kardashian, in an effort to obtain his DNA on the "on the low."
The two attempted to steal Rob's toothbrush without being seen and were immediately caught in the act by Rob, who agrees to just go take the test himself.
After the soon-to-be-parents decided to have nurses come out to their home to do the test, it turns out Rob really is the baby's father. The result came as no surprise, however Rob said he would have liked even more certainty from the test, which read “99.90%.”
"How do we get 100% probability?" he asked. As Chyna yelled at him for being overdramatic, Rob laughed. "No I’m just playing with you, I’m just super happy!"
"This baby is like, super, super, super blessed to have a daddy like Rob," Chyna said in a solo interview after the paternity test. "Because I know for a fact Rob is always going to take care of her and always have her best interests."
Despite their tumultuous roller coaster of a relationship, which has been documented in stark clarity over the course of the six-part reality series, the pair decided to stick it out and try to work through their many issues.
In fact, Rob has plans to further expand their family before they've even welcomed their forthcoming baby girl. When Chyna asked Rob where he sees their family "five years from now," Rob answered, "I see way more kids."
"I see us in a new house that we're comfortable in," he continued. "Our space, that we can build a family in, and just being happy with you."
Rob took to Instagram before the show on Sunday to share an adorable video of himself and Chyna, celebrating the last year they've spent together.
"What a great year," Rob captioned the cute video montage. "I'm so Blessed to have met the best Mama in the world Chyna and I got my baby girl about to be here… CANT WAIT. THANK YOU GOD FOR DOING WHAT YOU DO!!"
Chyna's son, King Cairo -- whom she shares with ex Tyga (who's currently dating Rob's sister, Kylie Jenner) -- celebrated his fourth birthday over the weekend, and Rob also shared a super sweet pic of himself and his stepson-to-be going down a slide, side-by-side.
"HAPPY BIRTHDAY KING‼ THANK YOU for letting me see what a great Mama you got!" Rob captioned the heartwarming photo. "That was the first thing I fell in love with… The way she Loves FOR You is something I can't wait for ! Can't wait for the bond I'm going to have with my daughter so Thank You King for allowing me to see that! Everybody Loves You!"