Stefani gives a hand to her 6-month-old son during a family playdate in Beverly Hills. Plus: Madonna, Ashlee & Pete, Scarlett & Kate and more

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UNEXPECTED GUESTS

They didn't jump out of a cake, but they did burst into theaters around the country this weekend, from New York to Dallas – including the AMC Loews Palisades Center 21 in West Nyack, N.Y. (left) on Saturday – to surprise fans who came out to see their new movie, Jonas Brothers: The 3D Concert Experience.