The 'Old School' actor and Weber, who tied the knot three years ago, are already parents to two-year-old daughter Locklyn and are set to welcome a new arrival on August 5, reported E! online.
Speaking to chat show host Ellen Degeneres, Vaughn, 43, said, "This is the first time I've said anything. We're very excited."
After Locklyn was born, Vaughn revealed parenthood had given him a different purpose.
"I feel so grateful. You know, my wife's so great. But I got to tell you. Just the minute they come out, so beautiful and just so sweet - I was just so glad that everyone was healthy.