A spokesperson for Oprah said her mother was already laid to rest, People magazine reported.
No other details were given.
Oprah's mother was a teenager when she gave birth to her, and the philanthropist and TV star was raised by Vernita's mother, her grandmother, Hattie Mae Lee in Mississippi.
Lee is survived by Winfrey and Patricia Amanda Faye Lee, her daughter who she placed for adoption and later reconnected with.
She shared: "I'm a Christian lady, and if you're a Christian person, it helps you to deal with situations like that". But on Christmas Eve, nuns brought food and toys for Winfrey and her siblings. While one might think Oprah is always hustling, never worrying about others, she is, in fact, one of the biggest contributors to charity in the world. Oprah and her half-sister were famously reunited on her show in 2010.
"Coming to Waukesha County on a Saturday evening was not my idea of a great time", Winfrey said to an amused crowd. She was predeceased by son Jeffrey Lee (1960-1989) and daughter Patricia Lee Lloyd (1959-2003).
Winfrey has spoken about her rocky relationship with Lee in the past.
Our thoughts and prayers are with Oprah and her family during this hard time.
Winfrey said she had made peace with Lee's decision. "I was asking the question. what is a mother?"
Oprah's relationship with her mother, as fans of her legendary talk show may know, has been strained throughout the years. They moved to Milwaukee when Winfrey was 6 years old. Lee settled a $155,000 debt with Valentina Inc.in 2009. Oprah wrote that, at the time, she didn't really "know" her mother.