Sam Smith surprises radio hosts during marathon broadcast

They've been awake and on-air for more than 45 hours as ZM hosts Jase Hawkins and PJ Harding attempt to set a New Zealand record for the longest radio broadcast.

Yesterday, they received a major morale boost from international chart topper Sam Smith, who gave the pair a surprise interview halfway through their marathon broadcast.

The afternoon drive hosts were blindfolded and taken by car to Vector Arena, where Smith removed their blindfolds much to the hosts' shock and delight.

"I normally look so much better than this," squealed an embarrassed Harding.

The record-attempt is aiming to raise $100,000 for the Pin-a-Poppy appeal, which supports the RSA.

The pair began broadcasting at 3pm on Wednesday and will finish this evening at 6pm.

• Watch the livestream here.

The pair have taken to dancing in the studio in an attempt to stay awake and have been coaxed along with hourly treats, including spa treatments, cronuts and cuddles with puppies.

This morning, Hawkins revealed he had fallen off the toilet due to his sleep-deprived state and hit his head. Harding has also fallen off her chair.

A medical professional is on-site to monitor the pair's well-being.

- nzherald.co.nz