Sienna Miller reveals fiancé Oli Green proposed to her during a walk in Central Park shortly after giving birth to their second child together

Sienna Miller has revealed fiancé Oli Green proposed to her during a walk in Central Park shortly after giving birth to their second child together.

The actress, 44, and the model, 29, were confirmed to have gotten engaged in June by a representative after four years of dating. 

Now, appearing on Jimmy Fallon's The Tonight Show on Thursday, Sienna has revealed that Oli popped the question the day after she was last on the show on May 14 – three weeks after giving birth.

Detailing the proposal, she said: '[We] went for a walk in Central Park, popped the old question.'

'And you just had the baby,' Jimmy said.

'Yeah, I was not looking my best,' Sienna laughed before Jimmy asked: 'Wait, did you know it was going to happen?'

She replied: 'No, not in the slightest. And when I kind of got the feeling something was up, I was like, "Please God, not now".

'I had the greasiest hair, sort of stains on the T-shirt. It was, yeah, it was full postpartum beauty.

Jimmy said: 'So a nice romantic stroll and you're like, "Oh this is cool".'

Sienna continued: 'Yeah and then, "Why is he being weird?". Suddenly, chat, chat and then quiet and a bit sweaty-palmed. 

'I was like, "Please God no". I was like,"Ooo this is romantic."

'Oh like, you know, "Look at the birds", you know.

Sienna then went on to reveal that the pair met at a Halloween party while she was dressed as David Bowie.

She said: 'And then we got together seven years later at the same Halloween party, isn't that weird?'

Confused, Jimmy asked: 'Wait. Explain?' 

Sienna clarified: 'When we met, we didn't get together. And then seven years later at the same Halloween party, it was where we first smooched.'

'Wow! That's special,' Jimmy gushed.  

As well as her newborn son, Sienna and Oli also share a daughter who was born in early 2024.

The actress also has a 14-year-old daughter, Marlowe, with her ex Tom Sturridge.

Sienna told Vogue: 'I'd wanted another baby for so long that my postpartum was just bliss. I had thought, by the time I was 40, that it wouldn't happen.

'That I'd have my one baby and I kind of made peace with it. It was such a surprise, and it was such a bonus that I was just euphoric. I felt existentially relieved.'

She also spoke about finding first time motherhood a challenge after she had Marlowe as 'there wasn't as much focus on postpartum then'.

Sienna had an emergency C-section with her first daughter and has said she felt 'disappointed' and like she had 'failed' when she had a tough time postpartum.

When she welcomed her third child this May she planned and prepared for a natural birth, after two previous C-sections.

Sienna explained: 'I really wanted to have a natural labour with my third, which is kind of unheard of – especially after two C-sections. And I did it.'

She enlisted the help of Dr Gowri Motha and the Gentle Birth Method, a programme that 'blends self-hypnosis and visualisation with Ayurvedic teachings'

However, despite the natural birth and subsequent postpartum care she received she still regrets going back to work so soon.

She appeared on The Tonight Show Starring Jimmy Fallon five weeks after giving birth and has now said: 'It was all too much. I thought I could manage it, but it was just complicated and hard.'

She announced she had welcomed her third child in May, simply saying: 'It's happened. I have a tiny baby next door.'

Sienna announced her third pregnancy by revealing her blossoming bump at the star-studded Fashion Awards in December.