Heavily pregnant Tamsin Egerton shows off her baby bump under a summery orange top as she and partner Josh Hartnett take one-year-old daughter for a stroll in London

She's heavily pregnant with her second child with Josh Hartnett.  

And actress Tamsin Egerton proudly displayed her blossoming baby bump under a summery orange top as she and her partner stepped out for a walk in London on Tuesday.

With them was their 18-month-old daughter, whom the glowing Tamsin carried lovingly as Josh strolled along with the pram.

Their daughter - whose name remains unknown - held on to her mother and gazed adoringly at her father as they ambled around the capital in the warm June weather.

The casual get-up was a far cry from their glam turn out at the preview party for the Royal Academy Summer Exhibition on last Wednesday.

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Ready to pop: With them was their 18-month-old daughter, whom Tamsin carried lovingly as Josh strolled along with the pram

The happy couple joined an array of celebrity guests at London’s Burlington House ahead of the event, which serves to promote art and artists through a series of exhibitions and debates, as they enjoyed their night off from Mum and Dad duty.

The couple, who welcomed their first child in 2015, have kept tight-lipped about their pregnancy, but Tamsin appeared to confirm she was expecting at the Vanity Fair Oscars after-party in February, as she poked fun at her pregnancy diet with fellow guests.

According to People, the St Trinians actress had indulged in a few beignets at the bash - before she joked of the fried pastry snack: 'This is not feeding the baby nourishment!'

Last year, Josh spoke about how much he loves being a parent, as announced on the Live! With Kelly and Michael show last year that it had put 'everything into perspective'. 

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Stepping out: The actress, 28, wore a grey and white long skirt as she walked along - a blue handbag on one shoulder, her blonde locks tied up neatly on her head. Josh, 38, kept it casual in a white T-shirt, jeans, a black baseball cap and shades

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Blooming lovely: The casual get-up was a far cry from their glam turn out at the preview party for the Royal Academy Summer Exhibition on last Wednesday

He said: 'I mean, your ego melts away when you have a new kid. Your heart kind of leaves your body and you give it permission to walk around with someone else for a while.

'It’s really terrifying but it’s beautiful. I love it more than anything. I wish I would have started it earlier. But I’m so glad that she is the one I’m raising.'

After admitting that he's been very tired of late, Josh gushed: 'The best moments are when you have those individual moments alone in the middle of the night.'