ET spoke with the 62-year-old media mogul at the Queen Sugar premiere at the Warner Bros. Studio Lot in Burbank, California, on Monday, where she stunned in a fitted black, La Petite Robe di Chiara Boni knee-length dress, which showed off a little bit of shoulder. A pair of open-toe heels, square frame eyeglasses and a sleek ponytail completed her effortless look.
Winfrey acknowledged to ET's Nancy O'Dell that keeping up her weight loss has taken plenty of hard work.
"[Being on a] movie set, you know, it's so hard," she admitted, referring to currently filming the HBO movie The Immortal Life of Henrietta Lacks. "You know, you are working those long days, and then by the end of the day you're like, 'Oh my God, a bag of hot Cheetos calling your name.'"
"You have to leave the craft table and ask for a plum," she added.
"I'm counting the points every day and slowly it's happening," she shared. "I love it."
She also revealed that she doesn't actually have a goal weight in mind.
"It's a feeling where you get to the point where [you think], 'Oh I can go to the store, I can pick that size, it's available, I don't have to, like, have it altered and all that stuff,'" she explained about her ultimate goals. "So, I'll know when I'm there."
Winfrey has been busy promoting Queen Sugar, a new drama on OWN following three siblings -- Nova Bordelon (Rutina Wesley), Charley Bordelon (Dawn-Lyen Gardner) and Ralph Angel (Kofi Siriboe) -- who reunite at their family's 800-acre Louisiana sugar cane farm after a family tragedy. Oprah co-created the series with Selma director Ava DuVernay, and the two assembled an all-female directorial team, including Neema Barnette, Kat Candler, Tina Mabry, Salli Richardson-Whitfield, Tanya Hamilton, So Yong Kim and Victoria Mahoney.
"That woman's voice and that point of view is something that I had to have," DuVernay told ET last month. "We opened it up and hand-picked some brilliant directors to collaborate and the results are stunning."