NEW YORK (Reuters) - Supermodel Christie Brinkley began divorce proceedings against her fourth husband, architect Peter Cook, his attorney said on Thursday.

Brinkley served her husband with a summons, Cook's lawyer, David Aronson said.

"Last night we accepted service of the summons," he said, explaining that marked the first step in moving ahead with a divorce.

Brinkley's lawyer, Eleanor Alter, could not be reached for comment.

Brinkley and Cook, 47, announced in July they were separating after 10 years of marriage.

The announcement followed revelations Cook had an affair with a teenager whom he had hired to work in his firm.

Brinkley, 52, was previously married to artist Jean-Francois Allaux, singer Billy Joel and real estate developer Richard Taubman.

Brinkley's career as an all-American supermodel has spanned more than three decades. She has appeared on more than 500 magazine covers, in numerous television shows and been a spokeswoman for charitable and activist groups.