(dailymail.co.uk) - They have insisted, despite all the rumours, that they are nothing more than friends.
Yet pictures of Sienna Miller and Rhys Ifans which emerged over the weekend in Notting Hill, where Miss Miller has a home, seem to leave no doubt that the pair are indeed an item.
The pair were photographed taking 26-year-old Miss Miller's two dogs for a walk in the fashionable enclave of west London hand-in-hand and occasionally stopping to embrace and lock lips.
At one point, they cosied up to one another in the unlikely surroundings of a graveyard for an intimate kiss.
The couple have been constant companions for weeks and are most often pictured lurching from party to party around London.
They have consistently denied they are dating, and Sienna insists Ifans has merely been sleeping on her couch since his London houseboat flooded.
This summer they went on holiday on the hedonistic party island of Ibiza and last month they were in Dublin where Ifans, 39, best known for his role as Hugh Grant's slovenly flatmate in the film Notting Hill, had a dainty bird tattoo on his wrist to match the one Sienna already had on hers.
Sienna first became famous as girlfriend of actor Jude Law, who she starred with in Alfie, the remake of the Michael Caine film.
Law proposed to his young lover in 2004, but the relationship was blown apart after it emerged he had an affair with his children's nanny.
Despite successive attempts to rebuild the relationship, Law has been out of the picture for some time.
While Ifans is an actor of considerable talent, Miss Miller is still better known for the men on her arm - and her Boho chic dress sense - than her acting ability.