Where there’s a will there’s a war.

A Manhattan woman claims her resentful stepsons duped their elderly dad into starting divorce proceedings to keep her from her share of his estate.

Jennifer Gao, who was 27 years younger than spouse Anthony J. Walton, accuses his sons of hating her because she started dating their dad while he was still married to their mom.

Despite their tawdry beginnings, Gao insists in a Manhattan Supreme Court lawsuit that she and Walton had a “long and loving 23-year relationship,” which included a decade-long marriage to the international banking exec.

But before the 75-year-old Walton’s death in January following an aneurysm and a fall, his kids Philip, 54, and Charles Walton, 46, allegedly “coerced” him into signing a new will which cut Gao out.

Under a 2017 will, Gao, 50, is due one-third of the value of Walton’s estate, and their marital home at 197 East 76th St.

The couple met in 1995 when Gao was 26. She left her job at American Express to “take care of Tony,” she charged in her Manhattan Supreme Court lawsuit against the brothers.

Gao claimed in court papers that when Walton died he “considered her the love of his life” and “the best thing that ever happened to him.”

Neither Gao nor the Waltons returned messages.