02/12/2007 at 01:00 AM EST
In Europe, they call it the "Posh Shop Hop Photo Op" when former Spice Girl Victoria Beckham
methodically hits runway shows and boutiques, seeming to subsist on caviar and champagne. Learning the ropes on two recent Paris trips: her pal Katie Holmes
, free of baby weight and looking newly glam. "When Katie's shopping by herself, she's pulled together but casual," says a source who saw the pair during Beckham's January house-hunting tour of L.A. "With Posh, they are both dressed up, almost like echoes of each other in perfect thread-count harmony." Like Holmes's look in the March Harper's Bazaar
? Credit Beckham, who acted as guest fashion editor. "Victoria has a strong sense of style—she knew the pieces she wanted Katie to wear,"says Bazaar editor-in-chief Glenda Bailey. "Katie's style is very easy, laid-back." Well, not always: Witness her stunning solo turn at the Armani Privé show. Posh would be proud.