It looks like Sienna Miller is going to have to start preparing for a new role – mom!

The British actress is expecting her first child with boyfriend Tom Sturridge, a source confirmed to Us Weekly.

Miller, 30, and the 26-year-old actor (who is good friends with Robert Pattinson) have been together since last March.

But don’t hold your breath for a shotgun trip down the aisle. The source also said that they “don’t have plans right away to marry, if at all.”

The couple started dating shortly after Miller’s split from longtime love Jude Law.