The 55-year-old actor has been dating air stewardess Kayte, 29, since August, with the pair announcing their engagement earlier this month.
Earlier this year Kelsey split from his third wife, former Playboy model Camille Donatacci, after she cited irreconcilable differences, and the actor is eager to tie the knot again.
"Kayte and I are marrying because we are engaged, and we are engaged because we are in love and see no reason to postpone our happiness any longer," he told People magazine.
The star hasn’t given away any details on where and when the ceremony will take place, as he hopes to keep the big day low key. Kelsey and Kayte’s day is expected to be an intimate affair, with the pair surrounded by close pals.
"We are planning something we wish to be a private affair among several of our friends. Anything else is conjecture and false. Kayte and I are the only reliable source for this story. End of story," he added.
Kelsey has two children with Camille; eight-year-old Mason and Jude, who is six. He also has two children from previous relationships; Spencer, 27, and Greer, 18.
Kelsey and Camille were together nearly 13 years before she filed for divorce on July 6. By California law, there needs to be a six-month waiting period from the date the divorce is filed to the spilt being finalised, meaning their marriage could officially end on January 6.
According to reports Kelsey is set to pay Camille £32million in their divorce settlement as he didn’t sign a pre-nuptial agreement, meaning his wealth will be split in half.