JESSICA ALBA ENGAGED?Sexy Sin City actress JESSICA ALBA has sparked speculation she's planning to take a trip down the aisle, after she was photographed wearing a sparking ring on her wedding finger.The former DARK ANGEL star, 23, and her boyfriend CASH WARREN, 25, have been dating since January (05), after meeting on their set of her upcoming movie THE FANTASTIC FOUR.And while she was doing reshoots for the movie in the Canadian city of Vancouver, Alba was spotted walking with Warren on 8 April (05), wearing what appeared to be an engagement ring.But the actress' representative insists there's a simple explanation amid all of the fuss, stating, "She is not engaged. She's had the ring for a while, usually wears it on her right hand, but it was swollen (from flyin g), and she switched it."Alba says the ring is "a gift", but refuses to reveal who handed it to her.