Fifth Harmony have wished 5 Seconds of Summer a happy birthday.

The group recently celebrated their 3rd anniversary and their US peers sang 'Happy Birthday' for them whilst appearing on a US radio station.

They decided to sing the song in a punk-rock style in honour of the Australians.

Fifth Harmony meanwhile are due to release their debut UK single 'BO$$' on December 7.

The girls will perform the track on the X Factor on the same day.

The will feature on Fifth Harmony's upcoming debut album 'Reflection', which will hit shelves in the US on January 27.

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Watch 5H wish 5SOS a happy birthday below: