Amidst the backdrop of promoting his tell-all memoir, an heir to the Barneys luxury brand found himself embroiled in a shocking tax-fraud lawsuit, courtesy of his estranged brother, The Post has discovered.

Gene Pressman, aged 74, was at Rizzoli Bookstore in Manhattan last Tuesday to sign his latest release, “They All Came to Barneys: A Personal History of the World’s Greatest Store,” when he encountered a startling turn of events, according to sources familiar with the situation.

Among the queue of fashion enthusiasts waiting for their copies to be autographed, a “process server” — a professional tasked with delivering court documents — had mingled discreetly, reportedly after purchasing the book, sources revealed.

When the process server’s turn arrived, instead of presenting the book for an autograph, he produced a lawsuit and served it to Pressman, sources noted.

This legal action stemmed from his 71-year-old brother, Bob Pressman, who, as The Post exclusively reported last month, has accused Gene, their two sisters, and the late mother, Phyllis, of masterminding a sophisticated tax evasion strategy that allegedly deprived New York state of $20 million.

“Gene lost his composure — he yelled and used profanity against him,” a source with knowledge of the bookstore episode recounted. “He was visibly agitated by the incident.”

Randall Fox, a lawyer representing Bob Pressman, confirmed that Gene Pressman was “not a happy camper” and that he “cursed” when he got the suit, but the attorney declined to elaborate on the incident.

“It makes no difference for the case whether [Gene] Pressman received the service of process with grace or without,” Fox told The Post. “What matters is that he was served with process and now his 20 days time to respond to the case begins.”

Gene and Bob’s sisters – Elizabeth-Pressman Neubardt and Nancy-Pressman Dressler – live in the New York metro area and were already served, according to Fox.  

Gene — who lives in West Palm Beach, Fla. and was visiting New York for his book tour — did not respond to an email and phone message seeking comment. Bob Pressman declined to comment.

The bombshell civil suit – which only came to light after a judge unsealed it in June – claims that the allegedly tax-cheating members of the Pressman family could be liable for upwards of $50 million in back taxes and penalties.

The amended complaint, filed in New York State Supreme Court, lists Bob Pressman as a whistleblower under the New York False Claims Act, which could entitle him to up to 30% of any recovery. He filed his original complaint in July 2024. 

The suit alleges that his family falsely claimed that their mother, Phyllis Pressman, resided in West Palm Beach, Fla., to avoid paying the Empire State’s onerous estate tax.

In fact, the widow of retail legend Fred Pressman – who famously transformed his father Barney’s men’s suit business into a luxury empire in the 1960s – had been living year-round in her oceanfront mansion in Southampton, NY, for the last six years of her life, the suit claims.

Phyllis Pressman passed away last year at age 95 – and left her youngest son, Bob, nothing from her estimated $100 million estate, according to the complaint.

Her assets included the 2.3-acre, oceanfront spread at 346 Meadow Ln. in Southampton that’s currently on the block for $38.5 million. Her swanky Upper East Side apartment, listed for $3.95 million, is in contract.

Bob Pressman and his siblings had worked together at Barneys, presiding over an aggressive expansion and bankruptcy filing in 1996. Their relationship deteriorated after the family sold their stake in Barneys more than 25 years ago.

As exclusively reported by The Post, Bob Pressman had previously worked on an as-yet-unpublished manuscript for an incendiary tell-all book that blamed his family for Barney’s demise. 

The manuscript was never finished, sources told The Post.

In it, however, Bob accused his brother Gene of running Barneys into the ground with lavish spending projects, even as he allegedly spent his time partying through the 1980s at Studio 54.

At the time, Gene fired back, accusing his brother of having “a casual relationship with the truth” and claiming, “Bob conveniently forgets he was in fact the co-CEO responsible for the financial stability of firm, a role in which by all measures he massively failed.”

Bob was cut out of his mother’s will after years of family squabbling, capped by his refusal to participate in the alleged tax fraud, according to a source close to the case. A trust agreement drawn up by Phyllis’s attorneys declared, “Bob doesn’t get anything for reasons he well knows,” a source close to the case told The Post. 

Bob’s sisters, Elizabeth and Nancy, who were buyers for Barneys, sued him several years after the retailer’s 1996 bankruptcy, accusing him of cheating them out of $30 million from the business. Bob, who was in charge of the company’s finances at the time, denied the allegations.

A New York judge awarded the sisters $11.3 million in 2002. Their brother appealed the award.