Sienna Miller's stepmother Kelly Hoppen has said that the actress is pregnant with her first child.

The interior designer - who used to be married to the star's father Ed - said Miller and her boyfriend, actor Tom Sturridge, were looking forward to becoming parents.

The couple are understood to have been together for less than a year.

"Sienna is definitely not engaged or getting married... she is pregnant," the Telegraph quoted Hoppen as telling London's Evening Standard newspaper.

Rumours have been in circulation in the show business world for weeks that Miller, 30, was expecting.

The speculation was fuelled by Miller's withdrawal from her role with her fashion label Twenty8Twelve, with which she and her sister Savannah were co-creative directors. (ANI)