A friend of the "It Takes a Thief" star says Wagner, now 78, contends in the book "Pieces of My Heart" that the 43-year-old Wood's 1981 drowning probably happened when she slipped into the water while attempting to secure the loose dinghy, The Sunday Times of London reported.

"Now he thinks that Natalie heard the dinghy banging loosely against the Splendor, went to fix it and slipped on the 'swim step,' knocking herself unconscious, and rolled into the water, and the dinghy just floated away," the unidentified friend said.

"There was no conspiracy, nobody walking in on something sexual, nothing absurd like that."

Authorities determined Wood had been drinking the night she died though likely wasn't drunk. The heavy clothes she was wearing likely weighed her down, they said.

The Times said the forthcoming autobiography will mark the first time in 27 years Wagner has detailed in length the night of his former wife's death.

The celebrity couple was on board their yacht near Santa Catalina Island along with actor Christopher Walken. The newspaper said Wagner admits in "Pieces" that he was jealous of Walken's cinematic works, which included filming "Brainstorm" with Wood.