Islanders Brianna Langdon (26) and Sam Le Sueur (26) first met Miss Millane (22) while on a two-week guided group tour of South America at the end of October.
Miss Millane disappeared from Auckland on 1 December and was found dead in the Waitakere Ranges area west of the city a week
later. A 26-year-old man, who has been charged with her murder, is being held on remand and is scheduled to appear in the high court in January.
Miss Langdon said: ‘Grace was a very bubbly person. She always had a smile on her face and was always up for a laugh.
‘We all hiked the Inca Trail together to Machu Picchu, which took three days and was one of the highlights of the trip.’
Mr Le Sueur added: ‘The entire experience of travelling in a group like that means that you get to know each other very well and incredibly quickly. Grace was just a really lovely person.’
The couple both said that Miss Millane had particularly enjoyed the three-day hike to Machu Picchu, adding that they spent a lot of time with her over those three days.
They added: ‘We had been together since leaving Peru on 27 October, until arriving in Bolivia on 16 November, and we last saw Grace the day after that trip finished on the 17 November in Bolivia, when we all said goodbye to each other.’
Both Miss Langdon and Mr Le Sueur said they believed that Miss Millane, who was travelling alone, had booked her trip to New Zealand while travelling with them and seemed to be open-minded about where she would head to next. They added that she had mentioned plans to go to Fiji after her time in New Zealand.
The couple said they were both in shock when they heard Miss Millane had gone missing and were devastated when she was found dead days afterwards.
Mr Le Sueur said: ‘You see stories like this on the news all of the time but you never think that it would happen to someone that you know.’