'Lost my best friend last night' Olivia Wilde mourns the death of her beloved pet dog

Olivia Wilde has sadly revealed that her beloved pet dog has passed away.

The actress opened up about her loss on Instagram yesterday by penning a heartfelt tribute to the hound.

'Lost my best friend last night. Paco was a kind, wise, gentle, loving soul. I could post a thousand photos of so many adventures. These pics remind me of how peaceful he made me,' she said.

'My heart feels broken right now. All I can ask is that you consider adopting a pup, and loving them with all you've got. Here's to all the incredible friends of Paco who've been so kind to him over the years. I am forever grateful.'

The black and white photos Olivia selected to accompany her moving words were simply adorable.

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[/instagram] In the first shot, Olivia's fluffy white pet rests his head on her shoulder. The duo look blissfully happy in one another's company.

The second sees mum-of-two Olivia nuzzling against Paco's snout while he takes a snooze on the sofa.

Olivia's final two images continue to prove that the pair had a very strong bond.

The news deeply saddened a number of the Hollywood star's 2.7million followers on the picture-sharing platform.

Many rushed to share their condolences.

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[/instagram] 'I'm so sorry for your loss. He was a handsome boy and knows that you loved him. Hope you find comfort to heal your broken heart,' said one.

Another added: 'God bless him. Remember how much pure love he gave you and you gave him. Treasure the memories, he was lucky and you were lucky to have each other.'

A third user of Instagram made it clear that she understood exactly what 34-year-old is going through.

'My mom and I just went through the same heart break last week when our 18 year old pup passed,' they sympathised.

'We had her since birth in 2000. My heart is with you.'

Olivia - who is best known for starring as Dr Remy Hadley on American medical drama House - is engaged to fellow actor Jason Sudekis, 42.

The couple have two children together. Their first, a boy called Otis, was born in 2014. A little girl named Daisy followed in 2016.