The already frosty relationship between Julia Roberts and her big brother, Eric, has hit an iceberg now that the 68-year-old Dark Knight actor is bashing his sister’s acting chops in his new memoir! 

Just months after revealing in an interview Julia, 65, had ordered him to not talk about her in public, Eric admitted, “But I do!” 

While he apologized for a 2018 interview in which he claimed credit for Julia’s stardom — admitting he made it up — he slammed her performance in the 1989 movie Steel Magnolias, which earned Julia her first Academy Awards nod. 

“Julia was good in Mystic Pizza, great in Pretty Woman, but not so much in Steel Magnolias, in my opinion,” writes Eric, an Oscar-nominated actor. 

“I don’t want to sound like an actor talking, or a jealous sibling, but I don’t think her performance held up in that movie.”

The often-troubled Eric — Julia froze him out of her life for over 20 years before reaching an uneasy truce in 2004 — also tells bizarre stories about Julia, including the whispered rumor the sibs shared an incestuous relationship! 

A friend says Eric’s new book has Julia seeing red. 

“Julia is 12 years younger than Eric and he had already moved out of the house by the time she was in second grade,” dishes the friend. “She says Eric actually knows very little about her, and that he used her life to help sell his book is unforgivable — but she won’t tell him so.” 

“She would rather never speak to him again!”