It was last summer when we first learned the story of physicist Sterling Backus who, together with his young son, decided to build their own Lamborghini Aventador. Thanks to Backus' brilliant mind, his son Xander's enthusiasm and own ingenuity, and 3D printing technology, they began their dream project.

That was a year and a half ago and their homemade 3D printed Aventador is still not done. But that's okay. It's the build process itself that makes for a true father-son bonding experience.

And then Lamborghini heard about their little project. Instead of Santa Claus arriving a few days ahead of schedule this Christmas, Lamborghini reached out to the elder Backus with a fun idea.

He immediately agreed but wanted it to be a surprise for his son. On one cold Erie, Colorado morning, Lamborghini quietly made a delivery to Backus household. A black Lamborghini Aventador S (yes, a real one) was swapped in place of the still unfinished replica. The Backus boys opened the garage shortly afterward and Xander's face says it all. You can see how everything played out in the included video. You might shed a tear. Or several.

There are still plans to complete the 3D-printed Aventador, but for a few days this month, Lamborghini let the Backus family borrow an Aventador S. It's a wonderful story, but Lamborghini is still generally opposed to people building fake Lamborghinis.

"Automobili Lamborghini is against any attempt at counterfeiting. However, a true story of such authentic passion deserves to be featured, which is why we chose to tell of Sterling's and Xander's project in our 2019 Christmas video," said Katia Bassi, Chief Marketing and Communication Officer of Automobili Lamborghini.

Clearly realizing that Sterling and Xander Backus are true Lamborghini lovers with no bad intentions, the automaker did the right thing. It also secured the loyalty of young Xander Backus for life.