By Amber Goodhand - Radar Reporter
"I haven't met any of my grandchildren, but I'd like to meet them one day," Bill told RadarOnline.com in an exclusive interview.
"I hope to make amends."
While Bill, 62, acknowledges that there was a time in Kate's adult life when the two reconnected, he said that once she married Black Crowes frontman Chris Robinson and had their son Ryder, the relationship fell apart again.
"By 2005 it was back to absolute nothingness… I regret that I was absent from their life for a long period of time," Bill said of his estrangement from Kate and Oliver Hudson. "I should have fought harder."
Kate, 32, has two children -- eight-year-old Ryder with Chris and six-month-old Bingham -- with current fiance Matthew Bellamy.
Since divorcing Goldie Hawn in 1980, Bill, once a member of the legendary band, The Hudson Brothers, has remained relatively quiet in the media regarding his family life, until now.
"The book in some ways is an apology to Oliver and Kate," Bill explained of his new tell-all book, Two Versions: The Other Side of Fame and Family.
"They're my children. They're not celebrities to me."