THERE was no lighting, no speakers or entourage and the location was down the road from a former atomic bomb testing site. But Jessica Mauboy was at ease on her outback stage.

The pop star literally embraced her fans at the Nullarbor Plain outpost of Watson.

The Darwin-born diva has been performing free acoustic concerts across Australia as part of the Indian Pacific Outback Christmas train journey, an annual fund-raiser for the Royal Flying Doctor Service.

Great Southern Rail uses the shows to thank the isolated communities along the route which help sustain the locomotive on its epic 4532-kilometre pilgrimage between Sydney and Perth.

The ARIA award-winning Mauboy was moved to tears by the greeting she received from the mostly indigenous gathering, many of whom had travelled hundreds of kilometres. ''It really took me back, just seeing the light in their faces,'' the 22-year-old said.

Students from Oak Hill Aboriginal School travelled 250 kilometres to serenade Mauboy with Jingle Bells.

Andrew, 20, from Ceduna, said it had taken him ''only two-and-a-half hours'' to get there. Like most of the 100 people present, he had camped at the site overnight, enduring the rarest of Nullarbor experiences - a prolonged, torrential downpour.