The former "7th Heaven" star and Grant married in 1985 and have one daughter.
But Collins said in a statement issued to E! News he and his longtime spouse "are moving forward separately in our lives."
"She has been my dearest friend and a loving mother," said Collins. "I know that we'll go through this process in a way that honors our family."
Grant, who starred on "V" and "State of Grace," told E! News her husband's divorce filing is a "surprise."
"I am devastated," she said. "I wish him the very best in whatever path he chooses to take. Twenty-seven years of marriage in Hollywood is the equivalent of 189 dog years. I was exhausted."
Exploding whale video goes viral on Internet
Gal Gadot cast as Wonder Woman for 'Batman vs. Superman'