Singer and her estranged husband Mario Singer announced their separation after they got into a domestic dispute at their shared Hamptons home, where she caught the love rat with rumored gal-pal, socialite Kasey Dexter.
Zarin, who was fired from RHONY in 2011, commented on the report on Twitter.
"I am glad you finally told the truth @ramonasinger," she wrote about the situation. "I hope he gets what he deserves. Mario CHOKED her."
Singer retweeted one commenter's harsh reply to Zarin's comment.
"Why in the hell is @jillZarin discussing anything at all about @ramonasinger?" the fan asked. "STFU Jill. You nor your gossip are relevant."
Singer then tweeted: "Think it's sad she feels the need to use my personal business to try to make herself relevant."
The couple — who have one child, Avery — have continually denied marital problems and infidelities, but Singer finally filed for divorce after 27 years of marriage this week.
Speaking out for the first time this week, she tweeted: "Thank you all for the love & support! For my daughter's sake, I would appreciate everyone respecting our privacy during this difficult time."