Very sad news today out of the reality television universe:

Cassandra Waldon, a memorable CBS personality who became the first-ever Big Brother contestant to enter the house on the U.S. version of this program, has been killed.

She was 56 years old.

According to TMZ, the outlet that broke this sad piece of news, Waldon passed away on September 25 from injuries related to a car accident in Rome.

A source at the United Nations -- where Cassandra worked -- tells the celebrity gossip website that the ex-reality star struck by a vehicle about two months ago, suffering a head injury in the process.

Tragically, she never regained consciousness before her death.

The standout former Big Brother contestant is now being remembered and mourned by those who knew who well.

And those who remember her run way back in the day.

Host Julie Chen, for instance, wrote the following on Instagram:

"Thank you for bringing your intelligence, warmth and wisdom to the Big Brother house Season 1."

In the end, Weldon finished sixth out of 10 houseguests. In the history of the U.S. version of Big Brother, no contestant who entered the home first has ever come out on top.

The same actually holds true for the Canadian version.

Prior to her passing, Weldon worked at the UN as its Director of Communications for the International Fund for Agricultural Development.

She was living and working in Rome when the crash took place.

Fans of Big Brother are also speaking out on social media about this tragedy.

"Sad news, Cassandra Waldon of Big Brother 1 passed away last month," one fan wrote, adding:

"She worked at the U.N. at the time she was on the show, and was well-liked by her roomies and viewers alike."

Added another:

"Such a shame... She was my favorite contestant on season one. She was so thoughtful and smart."

Added Chen in her tribute:

"Your light will continue to shine in this world because of the way you lived your life: with class and grace... You are in my thoughts and in my prayers. May God Bless your soul."

TMZ reports that told her funeral will be held next weekend in her home state of Maryland.

May she rest in peace.

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