ISLAMABAD, Pakistan - U.S. Secretary of State Hillary Rodham Clinton says daughter Chelsea's approaching wedding in upstate New York is making nervous wrecks of both parents.

In an interview with NBC's Andrea Mitchell in Islamabad on Sunday, Clinton was asked about former President Bill Clinton's role in the ceremony.

"You should assume that if he makes it down the aisle in one piece it's going to be a major accomplishment," Clinton said with a laugh. "He is going to be so emotional, as am I."

The 30-year-old Chelsea plans to tie the knot with investment banker Marc Mezvinsky on July 31 in Rhinebeck.

Clinton stuck to her pledge not to reveal wedding details.

"My lips are sealed," she said, adding, "I am under very strict orders not to talk about," since it is a private matter.

Asked what she saw as the significance of this being an interfaith union, Clinton said it says a lot about the couple's relationship. Clinton is Christian; Mezvinsky is Jewish.

"Over the years, so many of the barriers that prevented people from getting married, crossing lines of faith or color or ethnicity have just disappeared," she said. "Because what's important is: 'Are you making a responsible decision? Have you thought it through? Do you understand the consequences?' And I think in the world that we're in today we need more of that."