Ah, to be four again! Kingston Rossdale, the eldest son of musicians Gwen Stefani and Gavin Rossdale, recently celebrated his fourth birthday in style. The couple put together a day of entertainment, family friendly fare and, of course, birthday cake that added up to a rumored $15,000 bill! Now that must have been quite a party! Pregnancy rumors have swirled around Stefani in recent months, but so far, the couple are parents to only Kingston and his 21-month-old younger brother, Zuma.