Tesla is known for hiding Easter eggs in its software updates. This holiday season, software version 2017.50.2 was released, bringing some holiday cheer to owners' electric vehicles.

On Christmas Eve, Tesla founder and CEO Elon Musk teased the arrival of the holiday-themed software update for the Model S and Model X vehicles.

"When you get the new Tesla software update, go Ho Ho Ho. There's an Easter egg inside the Easter egg, but it's not funny," he said on Twitter.

Once the latest software update is downloaded, owners will be able to see a reindeer button that activates "Santa Mode." Going by what Musk announced, the Christmas-themed mode can also be activated by pushing the voice command button and saying, "Ho Ho Ho."

When "Santa Mode" is activated, Chuck Berry's rendition of "Run Rudolph Run" will begin to play in the background. The dashboard display also transforms the car into Santa's sleigh. When turn signals are activated, drivers and passengers will be able to hear sleigh bells.

Meanwhile, for the Tesla models that are equipped with Autopilot, nearby vehicles that are detected by the system will be turned into prancing reindeers. The road also becomes icy with snowflakes.

As for the Easter egg hidden inside an Easter egg, the YouTube channel My Tesla Adventure discovered that saying "Ho Ho Ho Not Funny" into the voice command button will activate the song "Grandma Got Run Over by a Reindeer" by Elmo & Patsy.

Last Christmas, Tesla released the 8.0.2.50.15 software update which included an Easter egg that allowed the Model X's lights and Falcon Wing doors to perform a synchronized light show to the tune of "Wizards in Winter" by Trans-Siberian Orchestra. The performance started when the owner exited the all-electric luxury crossover, closed all the doors and pressed the lock button on the key fob.