Stella says she has done a few national anthems for the Bayleys National Sevens, but this would be performing to about triple the number of people.
It will be streaming live worldwide too.
She's looking forward to the atmosphere, which she thinks will be amazing because the stadium will be full and two confident teams will make for some great rugby.
"I love perfroming and I love singing. It's cool to have an international platform to do what I love and be part of a milestone event in our town."
There are many events on in Rotorua to celebrate the Maori All Blacks and British and Irish Lions game this weekend.
The Tima Tangata Maori Rugby Exhibition opened on Wednesday and will be running until June 23 at the Energy Events Centre.
The exhibition was originally showcased at the 2011 Rugby World Cup with great success and thousands visiting the exhibition.
Entry is a gold coin koha (donation) for adults and free for children.
There is also the International Rugby Club's Giant Haka event tomorrow at the Lakefront Village Green from 10.30am to 1pm.
It is an attempt to break the Guinness World Record for the Largest Haka and surpass the current record held by the French.
The Giant Haka is supported by Rotorua Lakes Council and the Rugby 2017 Festival, and features the famous Ngati Toa "All Blacks" haka Ka Mate.
The event is free to participate but people will be asked for a gold coin donation for a local community project in Rotorua.
Also tomorrow the final match in the International Women's Rugby Series, the Wallaroos (Australia) versus Canada will kick off at Smallbone Park at 12.30pm.
This game is free to the public, with all City Ride busses being free of charge for the weekend.
Hells Gate Rotorua Mud Rugby is launching on June 17, 18 and 19.
It will include muddy team events, mud activities, hangi lunches and cooking pool food tasting.
For more information visit www.hellsgate.co.nz. General admission is $35.