"I think I know why this is happening," the actor jokes

Credit: Chris Polk/FilmMagic

Chris O’Donnell and his wife Caroline Fentress are preparing to add yet another child to their ever-growing brood – their fifth.

On the Today show on Wednesday, the actor was asked about his four children. “Another on the way,” he replied, before high-fiving Today cohost Ann Curry.

He added, jokingly, “Yeah, we’re just starting to figure out how it works. I think I know why this is happening, but we’re really excited about it.”

The 37-year-old actor married Fentress, a schoolteacher, in 1997. Their four other children are Lily, 7, Chip, 6, Charlie, 4, and Finley, 16 months.

O’Donnell also mentioned on Today that he has just finished filming Kit Kittredge: An American Girl Mystery, a drama based on the American Girl line of dolls – a project which gave his daughter Lily a true movie-making experience.

“She came to the set and hung out for four days,” he said. O’Donnell is currently starring in the CIA miniseries The Company on TNT.