Pregnant Sienna Miller was all smiles during a stroll through her Primrose Hill neighborhood today. She stepped out in a short flowy dress and accessorized her baby bump with a low-slung belt. Sienna's been hanging in London while her fiancé Tom Sturridge traveled to Cannes for the world premiere of On the Road. Tom cleaned up his beard and wore a suit on the red carpet, where he posed alongside his big-screen costars Kristen Stewart, Garrett Hedlund, and Kirsten Dunst. Tom's best friend Robert Pattinson was also in Cannes to support Kristen and Tom's project. The film is expected in theaters later this year, which gives Tom more time to hang close to home with his own leading lady, Sienna.