Simpson-Wentz and her 3-month-old son arrive at London's Heathrow Airport. Plus: Christina & Max, Britney Spears, Justin & Jessica and more

WARM THOUGHTS

After soaking up some sun and sweets in Los Angeles, it's back to the blistery cold for Michelle Williams and daughter Matilda, 3, who keep warmly wrapped during a walk though their Brooklyn, N.Y., neighborhood on Tuesday.