Actress Carrie Fisher -- best known for her iconic role as Princess Leia Organa in the Star Wars franchise -- died on December 27 after suffering a heart attack, and celebrities have already posted all across social media to pay their respects to the late actress.

Seth MacFarlane, William Shatner, Anna Kendrick and Ryan Seacrest are among several stars who posted on Twitter after news broke that the 60-year-old actress had died, just days after she suffered cardiac arrest on an airplane (December 23).

While many celebrities paid tribute to Fisher as an actress and icon, others, like Halsey, pointed out the late star's mental health advocacy.

See how celebrities reacted to Carrie Fisher's untimely passing below, including musician Paul Simon who was married to Fisher from 1983-1984 and dated her on and off for nearly ten years.

"Yesterday was a horrible day," folk singer Simon tweeted on December 28. "Carrie was a special, wonderful girl. It's too soon."

Fisher's mother, Debbie Reynolds, noted via Twitter yesterday (December 26) that the When Harry Met Sally actress' status had been upgraded to "stable," though she remained in the intensive care unit of a Los Angeles-area hospital at the time.

But Fisher's daughter, Billie Lourd, ultimately confirmed her mother's death in a statement today via family spokesman Simon Halls, saying, "It is with a very deep sadness that Billie Lourd confirms that her beloved mother Carrie Fisher passed away at 8:55 this morning. She was loved by the world and she will be missed profoundly. Our entire family thanks you for your thoughts and prayers.”

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