America woke to a terror scare Monday.  The State Department is warning Americans to be cautious about traveling to Europe.  But hundreds of celebrities are already in Europe attending fashion week in Paris.

Janet Jackson was front and center at the Galliano show. Sarah Jessica Parker, Courtney Love and Liv Tyler also took in the shows.

A very pregnant Stella McCartney hosted a show filled with celebrities. Her legendary dad, Paul McCartney, sat in the front row. So did actress Salma Hayek and Vogue's editor-in-chief Anna Wintour, who refused to be cowed by the threat.

"Our plans are remaining the same as of now," she said in a statement.

Inside, the shows are going smoothly, but outside it's a security nightmare.  The Paris premiere of The Social Network drew celebrities like Justin Timberlake.

The world of sports is also on high alert. The New York Knicks are in Paris for a pre-season European tour. And the Los Angeles Lakers are playing today in London.

Tiger Woods is in Wales where the Ryder Cup Golf Tournament just ended.

On The View today, Joy Behar seemed worried, saying, "The targets are airports and hotels. What am I going to do?  Be homeless when I get there? I mean I don't want to live a week there with the anticipation of being killed."

The State Department decided to issue the alert after British authorities announced that "home grown" terrorists were planning some kind of an attack.