Sienna Miller donned a bright white gown on the set of The Girl in Cape Town, South Africa today. The actress showed little sign of a baby bump despite reports that she's expecting her first child with boyfriend Tom Sturridge later this year. Sienna's pregnancy news came at the beginning of the month, but that hasn't been the only excitement for Sienna and Tom. The couple are also apparently engaged, though they have no plans to wed anytime soon. If the baby and wedding rumors hold up, 2012 is bound to be a big year for Tom and Sienna, since Tom also has the release of On the Road in the coming months.