The 54-year-old "Kiss From a Rose" singer posted a meme of Winfrey and Weinstein that showed Winfrey kissing Weinstein on the cheek.
"Oh I forgot, that's right.....you'd heard the rumours but you had no idea he was actually serially assaulting young stary-eyed actresses who in turn had no idea what they were getting into. My bad," Seal wrote in the caption, adding the hashtag #SanctimoniousHollywood.
When the allegations of Weinstein's history of sexual abuse and harassment came to light in late 2017, Winfrey posted on her Facebook, saying, "I've been processing the accounts of Harvey Weinstein's hideous behavior and haven't been able to find the words to articulate the magnitude of the situation."
Weinstein and Winfrey had a longstanding relationship prior to his downfall in the entertainment industry, but he claims Winfrey continued to support him after dozens of women accused him of sexual misconduct.
Sources close to Weinstein told TMZ the disgraced producer repeatedly told his team that Winfrey called him to give advice, telling him he should speak out and defend himself against mounting allegations. Weinstein told them that Winfrey vows to be "right there supporting him" if he spoke publicly about the scandal.
Winfrey's spokesperson denies that the daytime TV queen ever reached out to Weinstein following the allegations, but said someone from his team contacted her to see if she would talk to him. She told him she would only speak if it was for an interview.
"She was interested if he'd look in the mirror and give her the honest, bone marrow truth," the rep said, adding that Winfrey was considering a 60 Minutes special with Weinstein.
At Sunday night's Golden Globes, Winfrey never mentioned Weinstein or any other men accused of sexual misconduct by name, but she called for "a new day on the horizon" if both women and men band together to elicit change.
"In my career, what I've always tried my best to do, whether on television or through film, is to say something about how men and women really behave. To say how we experience shame, how we love and how we rage, how we fail, how we retreat, persevere, and how we overcome," she said while accepting the Cecil B. de Mille award. "I've interviewed and portrayed people who've withstood some of the ugliest things life can throw at you, but the one quality all of them seem to share is an ability to maintain hope for a brighter morning, even during our darkest nights."