Sienna Miller has fallen for her new co-star Sean Bean, it has been reported.The actress, who is said to be smitten with the handsome 'Lord of the Rings' star, recently invited him to spend a romantic evening at her west London home and even cooked Sean a special beef stew. A source told Britain's Daily Mail newspaper: "She is completely mesmerised by Sean already. She has told friends that she can't help feeling transfixed by his green eyes and loves the fact that he is a real macho man."Sienna, 25, and Sean, 48, are due to start filming Oscar Wilde's 'A Woman of No Importance' in September.The 'Layer Cake' actress is said to be phoning Sean constantly and has dismissed the sizeable age gap between them.The source added: "He is almost twice Sienna's age but she doesn't care about that. She has dated many men of many different ages, so the fact he is a bit older isn't an issue for her. She is hoping to get to know him a lot better."Sean, who has three children, most recently dated 29-year-old actress Georgina Sutcliffe but the pair are said to have split following a heated row in Los Angeles.Sean's first marriage to his school sweetheart Debra James ended in the 80s after he moved to London to attend prestigious acting academy RADA. He was married to actress Melanie Hill from 1990 to 1997, during which the couple had two daughters, Molly and Lorna.He then tied the knot with his 'Sharpe' co-star Abigail Cruttenden and had a daughter Evie Natasha. The pair divorced in 2000.Sienna has previously dated Jude Law and Daniel Craig, and was most recently romantically linked to rapper P. Diddy. Her publicist has denied Sienna is dating Sean, insisting the reports are"categorically untrue".