Megan Fox is engaged for a second time to Brian Austin Green . Apparently Green popped the question to the 24 year-old “Transformers” star June 1 but soon after lost the ring. “I saw her jumping up and down,” a witness told Us Weekly mag of the beachside proposal at the Four Seasons on the Big Island in Hawaii. “Later, I saw a half dozen staff sifting through the sand.” And, apparently, the 2-carat ring - which the pair picked out together - is still missing. “Security and maintenance staff spent a couple of hours looking for it,” another source tells Us Weekly. “No one found it.” Green and Fox began dating in 2004.