The digital release of “Umbrella” had the biggest debut in the history of iTunes, but it was almost Britney Spears who got to sing this worldwide Number One song, “ella-ella-ella” hook and all. With Spears’ career spiraling out of control at the time, songwriter and co-producer The-Dream said, “We thought, 'Let's save our friend.' ” But Spears' management brushed them off, and then second choice Mary J. Blige also passed on it, much to the unabashed delight of the Bahamian singer born Robyn Rihanna Fenty. “I'm so thankful for it,” she said. “I prayed for this song.”