While he had plans for a male version and mused about other gender variations, Harmony would launch as an artificial female with porn star proportions.
Harmony failed to launch in 2017, but Mc Mullen and his team have been hard at work, making improvements to Harmony's AI and the robotic head it's housed in.
On the eve of her debut, Harmony has ventured to the hotbed of consumer electronics with a new face, an updated AI and a few new friends.
If you happen to be at CES and want to see Harmony in the silicone flesh, she'll be live from Engadget's stage in the main hall of the Las Vegas Convention Center at 4PM PT today.
And if you're watching from home, tune into to watch our interview live at 4PM PT / 7PM ET.
Sex bots are hyper-realistic with features such as built-in heaters to create the feeling of body warmth. One company is even developing a head that can speak, smile and sing for its robot sex dolls, while sex doll Harmony is the first to offer an "emotional connection".
Experts say these specialised robots will start to appear in ordinary homes in the next decade, as lonely humans look for love.