Credit: Rick Diamond/

Little Lacheys!

Nick Lachey and fiancee Vanessa Minnillo haven't said "I do" quite yet, but that doesn't mean the groom-to-be isn't already thinking about fatherhood.

"I'd like to be a dad sooner than later," the 37-year-old told Parade magazine. "I'm getting up there. I've gotta catch up with my brother. [Drew's] got two and I've got zero, so the pressure is on me!"

Lachey has volunteered with Big Brothers Big Sisters since 2004. He said his time as a mentor for the organization has helped prepare him for fatherhood.

"I'm assuming fatherhood is going to be a hundred times more intense than being a Big Brother, but watching a life develop in front of you is a bit of a parallel," he said. "I'm certainly looking forward to it."

"I'm at a point in my life where I'm ready to start another chapter. Having kids is a big part of that. I'm excited for what comes next," he said. "Life is a journey, and I'm certainly ready to close this chapter and move on to the next."

After dating for four years, Lachey proposed to Minnillo, 30, in November 2010. (Lachey was famously married to Jessica Simpson from 2002 to 2006; Simpson announced her engagement to ex-NFL star Eric Johnson only days after Lachey shared his good news.)

But before he meets Minnillo at the altar, Lachey needs a bachelor party! "I'm fearful!" he admitted of the as-yet unplanned bash. "But we're going to have a great time. At this point in life you don't get to see the boys as much as you used to and a lot of the friends from college and stuff have moved on and have their own families. This is a chance for us all to get together and tie one on and have some fun again. We're all looking forward to it."