"I was just informed that at the age of 43, I am TOO OLD to play the wife of a 57 year old," the Orange Is the New Black actress tweeted on Wednesday.
"Oh, the characters also have an 18-year-old daughter. I am TOO OLD to be the mother of an 18 year-old," she added. "The real wife of the 57-year-old actor is EASILY AT LEAST 50. But this f****r wants to be TV married to a 38-year-old -- TOPS."
Denbo, who portrays Ginsberg in the Netflix drama, later took to Facebook to write a lengthy post about sexism and ageism in Hollywood after her tweets started a conversation on the issue.
"I didn't expect this to blow up -- even a little," she wrote. "I deliberately chose to not publish a personal blog post or a longer piece about it (there IS one sitting on my desktop) because I didn't want to completely blackball myself as an actor."
"Honestly - it mostly just hurt my vanity - which is pretty rare. I don't usually think of myself as 'old.' It stung like when your Junior High crush (the one with a little acne and baby fat) tells your friends that you're kind of ugly," she continued. "Also, there are WAY more important things to rage about in the world right now besides obvious and regular accounts of sexism (and ageism) in Hollywood."
The actress added that she was "gob smacked" by the casting moment "because I never watch terrible s**t with such dumb premises as having an old man f**k an improbably young wife anyway."
"I watch Orange Is the New Black, You're the Worst, Difficult People, Game of Thrones... all have amazing female characters of all ages and colors -- all brilliant and complex and interesting," she added. "I'll stop with one little word of advice to the 'creators' out there. Just make sure that whichever 30-something you cast is a SPECTACULAR actress, because don’t kid yourselves, she is gonna have to really work hard to make it look like she’s attracted to a 57-year-old."
This isn't the first time an actress has called out Hollywood's sexist casting notices. Crazy Ex-Girlfriend star Rachel Bloom previously shared a casting call on Twitter, which was seeking "a pretty girl" to play the lead, "attractive girls" for party extras and "sexy clothing."
"Here's a little taste of what it's like to be an actress searching for your next job," she wrote.
For more on Bloom and her Crazy Ex-Girlfriend character check out the video below.