The Sierra Canyon combo guard revealed the amazing gift on Monday ... saying, "This year I wanted to kick off the holiday season a lil different and got my mom a car."

"Thank you for all of the sacrifices to even make this dream of mine come true. I love you ❤️. Thought I’d beat you to getting the whip for you tho."

His mama, Johanna Leia -- who you might also recognize as Drake's one-time girlfriend -- was left speechless ... posting a heartwarming thank you note to her 17-year-old son.

The whip appears to be a 2022 Porsche Cayenne ... which comes with a starting price tag of nearly $70,000.

So, how does a high school kid pay for that?? We're guessing he took advantage of the NCAA's new NIL rules.

"I wasn’t gonna post anything because I’m an extremely private person. However, I am still shocked by what this truly represents," Leia said on IG.

"Amari, this truly speaks to your heart, your mind, your work ethic, and all of our long hours in the gym, and long talks in the car. All I’ve ever wanted is to see a smile on your face and no holes in your heart."

The sacrifice has paid off so far ... Bailey is one of the top high school basketball players out of the 2022 class and the 5-star recruit signed with the UCLA Bruins in November.

"My dream is to see you live yours and to help you in any way that I can," Leia said.

"But truly this is unbelievable that at 17 this is how you choose to say thank you and make me smile. Keep living your life Pooks."

Amari is also helping out two single mothers in Chicago this holiday season ... saying, "It feels good to know that I’ve worked hard enough to give back to my community."