Jude Law and Sienna Miller were full of smiles as they arrived at Heathrow Airport yesterday. The couple saw in 2011 in Kenya, and had lots to celebrate in the last week, as Sienna turned 29 on Dec. 28 and Jude turned 38 on Dec. 29. Sienna was in LA last month, but made it back to London in time to enjoy the festive season with Jude. They spent 2010 working on their reunion, and are entering 2011 with even more commitment, as they've bought a house together in Highgate. Jude's already filling it with presents, as he reportedly bought Sienna a grand piano with a sapphire-diamond ring hidden inside.