Sienna Miller and her boyfriend Tom Sturridge are reported to be expecting their first child together.
The couple, who have been dating for around a year, are claimed to have broken the news to friends and family over Christmas.
Sienna, 30, and 26-year-old actor Tom have not officially confirmed the news - but a tweet from her sister Savannah that simply read "THRILLED" has been cited as evidence in favour of the pregnancy.
A source told American gossip mag Us Weekly that they have no immediate plans to marry.
The mole said: "Friends are really happy with her relationship with Tom. He's younger, yes, but he's mature and he's a good guy."
And another US rag, Life & Style magazine, claimed that Tom had popped the question with a Victorian ring as they spent Christmas together in Paris.