“When he shaves off his mustache he’s got a hairline fracture, he’s got one of those — what do you call it? Cleft lip, cleft palate," said Williams, 55.
As she spoke, Williams pulled her lip up with her finger to mock the condition, which happens when a baby’s lip or mouth do not form properly during pregnancy, according to the Centers for Disease Control and Prevention.
Though Phoenix hasn't spoken publicly about the scar, an October 2019 profile about him in Vanity Fair described it as "not a surgically fixed cleft, he says, but a nonsurgical scar he was born with."
Late Wednesday, Williams apologized for her comments, writing on Twitter that her show plans to donate to organizations that benefit people affected with cleft lip.
The Oscar nominee hasn't responded to Williams' remarks, but many parents and activists have slammed the host's insensitivity.
Adam Bighill, a Canadian professional football player who was born with a cleft lip and palate and whose son Beau was also born with the condition, has been demanding an apology from Williams for days on Twitter.
"@WendyWilliams comments/actions towards the cleft community clearly promotes bullying," Bighill tweeted Wednesday.
Another angry father wrote, "For a solid 10 seconds she used her finger to mimic a cleft lip while the audience laughed. Imagine how my 5 year old would take it if he saw it?"
Carol Vorderman, a British TV personality who called herself an ambassador for the Cleft Lip and Palate Association, also condemned Williams.
“Mimicing (sic) a cleft lip, and making a joke about it, is disgraceful. Have you any idea the pain and operations a child with cleft must go through as they grow?” she tweeted.