Actress Sienna Miller, 43, has reportedly become engaged to actor Oli Green, 29, marking the fourth time she has been a fiancée, according to multiple reports. The couple, already parents to a two-year-old daughter, sparked rumors with a sparkling new diamond spotted on Miller's finger in Barcelona—just a week after she gave birth. friends quoted in the report describe the pair as 'so ridiculously in love' and having 'a lovely family'.

Oli Green and the 15-Year Age Gap the Friends Dismiss

Green, a British actor and model, is 15 years Miller's junior—a difference that friends of the couple brush aside. 'He knows what a catch Sienna is and wants to make her his wife,' an unnamed friend told the source. miller herself has been open about the relationship, telling reporters, 'I didn't expect to take it seriously and then quite quickly, I fell in love.' The age gap has not been a focus in previous coverage, but it is a notable detail as the couple steps into a formal engagement.

The Unknown Third Child: Born in May, No Name, No Sex Revealed

Miller gave birth to her third child in May 2025, but has yet to disclose the baby's name or sex, according to the report. she already shares a daughter, Marlowe, 13, with ex-fiancé Tom Sturridge, and a two-year-old daughter with Green. The new baby's secrecy has fueled fan curiosity, especially as Miller recently appeared at the Fashion Awards in December with a noticeable baby bump. She described the transition as challenging, saying, 'It feels like stringing sentences together is a bit challenging.'

Barcelona's Ring and the Fourth Time as Fiancée: Will She Make It to the Aisle?

The engagement was first noticed when Miller stepped out in Barcelona, showing off a diamond ring while leaving a party. This is her fourth time as a fiancée; she has never been married. Her previous engagements include a long-term relationship with actor Tom Sturridge and two others that ended before the altar. Onlookers in Barcelona said the actress 'couldn't stop smiling'. The source suggests friends hope 'it will be fourth time lucky and Sienna will make it to the aisle this time'. No official confirmation from the couple has been issued yet.

Miller's Jack Ryan: Ghost War Promo Tour: Balancing Baby and Bump

Miller is currently promoting her new action film Jack Ryan: Ghost War, and has described a 'nightmare flight' to the US while sleep-deprived with a newborn. She joked about the contrast betwen red-carpet glamour and motherhood, saying, 'It's crazy to be talking words and wearing a dress. What has happened from pajama gate.' The engagement comes amid this busy professional moment, and the couple is expected to atteend upcoming events together .