Sienna, Porgy and Bess

Proud pet-owner Sienna Miller chats on her cell phone while taking her dogs Porgy and Bess out for a walk around her London neighborhood on Friday.

Sienna, 26, had been scheduled to promote her new movie The Mysteries Of Pittsburgh at this month’s Sundance Film Festival in Utah. UK’s The Daily Mail claims Sienna was trying to avoid Sadie Frost, the ex-wife of her old flame Jude Law. Other media reports claim Sienna was too choked up about the death of her Casanova costar Heath Ledger.

10+ pictures inside of Sienna, Porgy and Bess…