A woman’s hilarious filter fail went viral after it appeared to show her father pleasuring a tyrannosaurus rex.

The poster, called Sierra, had planned to jazz up a video of her dad blowing out the candles on her birthday cake.

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So she chose the T-Rex filter, with the cyber-dino roaming across the screen as she finished singing ‘Happy Birthday to You.’

Sierra, who is from Indiana then said ‘Ok, blow it out dog,’ prompting her dad to lean forward and blow out the candles.

But the augmented reality dino chose the same moment to bend over and roar, making it look as if Sierra’s father’s face was buried in its behind.

She shared the fun fail on Twitter, writing: ‘Added the dinosaur filter while singing happy birthday to my dad and it went horribly wrong.’

It has since gone viral, with thousands of amused tweeters making jokes about the unfortunate timing fail.

One man called Carlos said: ‘thats what i call a mega-sore-ass.’

Ben wrote: ‘Jurassic world lost its 12R rating I guess.’

Tom said: ‘Ugh spoilers now we know how the humans and dinosaurs stopped fighting.’

And Sarah Raybould wrote: Wow fifty shades and Jurassic Park most ambitious crossover of 2018.’