Allison Janney's first Oscar win draws big reactions

Allison Janney won her first Oscar on Sunday for her performance as LaVona Golden, Tonya Harding's cold, abusive mother in "I, Tonya" -- and fans were quick to offer their congratulations to the 58-year-old actress.

"I did it all by myself," Janney joked as clutched the golden statue for Best Supporting Actress. The camera then panned to Margot Robbie, who was bent over in her chair laughing. 

"OK, nothing further -- nothing further from the truth," Janney continued as she thanked the Academy and praised the "extraordinary" nominees.

She then went on to name the "I, Tonya" castmates she calls "family," including Robbie, "cast and crew and bird" for elevating her work.

"I did not see this coming," she added.

At the end of Janney's charming acceptance speech, the actress turned serious.

"This is for Hal," she said. "You're always in my heart."

Janney's brother, Henry "Hal" Janney, committed suicide in 2011 after battling addiction.

Here's what the Twitterverse had to say about Janney's first Oscar nomination and win.

Celebrities praise the "brilliant" Janney

Fans "weep," congratulate "magnificent actress"

The Associated Press contributed to this report.