"Cass's eggo is preggo!" he writes on the premium section of his site. "We are excited about adding onto the family, but we aren't too sure how the current kids, Jake and George, are going to feel about it."
Jake and George are the couple's dogs.
Bentley, 33, and Cassidy, 32, eloped in 2006 in a little chapel in Mexico, where Bentley is now on vacation. "Mexico has always been a special place for us," writes Bentley.
He says the couple have "gone back and forth" on whether to find out the baby's gender. "At this point, we are keeping it a surprise until it happens this fall," he writes.
Bentley recently released Greatest Hits/Every Mile a Memory 2003-2008 with 10 hits, two new songs and five live recordings that his fans chose.