Property developer Laurence Hallier has filed a claim against the actress alleging she failed to promote the sale of his condominiums in the Panorama Towers in Las Vegas and cancelled a string of personal appearances connected with the venture.
The $22.5 million sum represents losses from the unsold units.
The suit comes after Pamela filed a claim against Laurence because she did not get the condominium he promised her for promoting the development.
In her suit, the former `Baywatch` star claimed she was entitled to a $1 million fee if she did not get the property, but Laurence insists she is not entitled to either because she failed out carry out her agreed duties.
Pamela and Laurence had a tumultuous on/off romance, but finally called time on their relationship last year.
The blonde sex symbol - who has two children, Brandon, 15, and Dylan, 13, from her marriage to Motley Crue rocker Tommy Lee - has battled money problems in recent years and moved into a trailer park last year while her home in Malibu, California, was being renovated.
She later claimed she enjoyed the simple life it afforded her so much, she never wanted to leave.
She said: "The boys and me love the trailer park, it`s a special community, we`re happy here.
"It`s the most beautiful place, it`s where I take my motorcycle, my surf board. There are firemen with their children, surfers, all sorts. The children are so happy. I wouldn`t trade my life with anyone."