Updated

As Heidi Klum says on "Project Runway," "In fashion, one day you're in, and the next, you're out."

The same goes for Internet popularity. That's why GossipCenter.com tracks celebrity online popularity 24/7 with their Gossip Center Hot 45 List.

The Gossip Center Hot 45 List is calculated by looking at the popularity of the site's hottest stories, and determining which stars are on the rise, and who is crashing and burning. All of the articles, pictures and videos on the Gossip Center Network are scanned for activity, and the rankings are updated several times a day.

This week saw Kate Hudson shoot to the top of the list, while Stephanie Seymour experienced quite the roller coaster ride.

Let’s see how this all played out.

Hudson has been getting more serious with her Muse man Matthew Bellamy, and now they’re taking things to the next level by having a child together. Kate’s reportedly 14 weeks along.

So, famous musician boyfriend + A-list actress + pregnancy news = #1 with a bullet.

Christina Aguilera nabbed the #2 spot thanks to her trip to Disneyland to help her son Max celebrate his 3rd birthday. People loved those photos!  Now that she and her husband Jordan Bratman are splitsville, Aguilera is trying extra hard to show their kid plenty of love.

Usually a top-of-list mainstay, Justin Bieber fell to #4 this week, though it could have been worse. A clip from his upcoming film “Never Say Never” helped him stay afloat.

Stephanie Seymour was the bobber of the week. She shot from obscurity all the way to #1, then fell back to #30 as a result of her oceanside smooch with her 17-year-old son Peter, and his subsequent public defense of their affectionate display.

Those are this week's movers and shakers. Check back next Friday to see how your favorite celebrities fared. And click here for the complete Gossip Center Hot 45 List.

Mike Lavalette is the editor of GossipCenter.com