The Extra host popped the question to Mazza - the mother of his young daughter - during a vacation in Mexico, with cameras on hand to capture the build-up.
Mazza's reaction and whether she ultimately accepted will be featured on tonight's (Wednesday, January 4) episode of Extra.
In a video shot moments before the proposal, Lopez says: "I've come to the realization that I'm never going to meet another woman as special and amazing as the one I have and I think she's finally succumbed to my pressure and will take me. So we'll see, I hope."
Watch Mario Lopez preparing to propose below:
In the video Lopez also reveals the engagement ring to viewers and wonders how he should pop the question, adding that his friends and family are present.
Former Saved by the Bell star Lopez and Mazza welcomed daughter Gia Francesca Lopez in September 2010, with Lopez saying at the time: "We are so overjoyed. What an amazing, wonderful and overwhelming experience to welcome our daughter into the world."
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