Zsa Zsa Gabor's Adopted Son Dies Just Days After Her Death

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Sad news for the von Anhalt family.

The late Zsa Zsa Gabor and her husband Frederic Prinz von Anhalt's adopted son, Oliver Prinz von Anhalt, has died, ET can confirm. Oliver was involved in a motorcycle accident in Los Angeles on Dec. 10, and died on Christmas Day -- exactly a week after Gabor died on Dec. 18.

"I found out everything from the coroner actually," Frederic tells ET.

WATCH: The Many Loves of Zsa Zsa Gabor: From Prince von Anhalt to John F. Kennedy

Oliver was riding a motorcycle when he got involved in a traffic collision on Mulholland Drive with another vehicle, according to California Highway Patrol officials.

"The motorcycle was traveling westbound at an unknown speed around the corner," authorities tell ET. "The other vehicle was traveling westbound at approximately 10 miles-per-hour preparing to make a U-turn on to the dirt shoulder on the other side of the street. The report says that either the motorcycle was going too fast for the roadway conditions, or the other vehicle was making an unsafe U-turn, but the officer on scene could not determine which was the cause."

"The motorcycle made an abrupt braking maneuver causing the rear wheel to lift up into the air and then he was ejected from the motorcycle," authorities continue. "[Oliver] was sliding on the ground for some distance and both bike and rider continued westbound sliding into the left side of the other vehicle."

Oliver "was conscious on scene but he was not able to answer any questions from the officer on scene," officials add.

Oliver stands furthest left in the photo below:

Getty Images

The late socialite was one of several men who bought their royal titles from Frederic through adoption when they were adults. Frederic himself got his title of Prince Frederic von Anhalt of Munich when he was adopted by Princess Marie Auguste of Anhalt as an adult, he told the Associated Press in 2007.

Frederic admitted he then made millions of dollars by passing the family title to at least 10 other people.

"If someone offers you $2 million, you do it," he told the AP.

One of Oliver's brothers through adoption, Marcus Prinz von Anhalt, mourned Oliver on Instagram with a video of the two together.

"Live the Afterlife in the fullest like you did before!" he also captioned a picture of Oliver in his royalwear.

NEWS: Looking Back at the Intriguing Life of Actress and Socialite Zsa Zsa Gabor

The pair's adopted mother, Zsa Zsa, died of a heart attack, according to her death certificate. Frederic, 73, told ET that his wife was home with him at the time, and "her heart just stopped."

The iconic actress was 99 years old.

Watch below:

-- Additional reporting by Steve Wilks