When most musicians cover a famous song, they usually don't expect to receive a personalised message from the artist.

But in a pleasant surprise, Pharrell Williams has praised Melbourne singer Gillian Cosgriff for her rendition of his hit track Happy.

The 41-year-old chart topper took to YouTube to call her cover 'amazing,' telling fans to 'check it out right now.'

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'It's amazing:' Pharrell Williams made a Melbourne musicians day after he posted a personalised YouTube video praising the singers cover of his hit song Happy

Gillian, a singer and pianist, put her talents to good use when she posted a YouTube video of herself covering Happy with a piano in the streets of Melbourne.

The video also featured three friends, one on guitar and two on backing vocals, and has since received over 200,000 views.

And while the comments on the four minute clip are all positive, the best praise undoubtedly came from Pharrell himself.

On his own channel the American star shared a short message to his over one million subscribers.

'Melbourne Australia, Gillian Cosgriff spreads happinesses with piano,' the Grammy Award winner said while appearing in his signature hat.

'Have you guys seen this? It's amazing, you have to check it out, right now.'

She's happy: The singer Gillian Cosgriff took to Twitter on Thursday to share her excitement over being recognised by the famous artist

In the moment: Gillian's cover song was shared on YouTube back in January and has since had over 200,000 views

Gillian took to Twitter on Thursday to share her excitement over being recognised by the respected artist.

'I just split my jeans in half jumping up & down because @Pharrell said my name on the internet, holy s**t,' penned the songwriter.

The famous shout out will no doubt provide a career boost for Gillian, who regularly showcases her talents in an array of street performances.

She was also the proud winner of best cabaret act at the 2013 Melbourne Fringe.