Coincidentally, Sheeran made a guest appearance on Shortland Street last year.
A South Pacific Pictures spokesperson told Spy it was "pulling out all the stops" for the Christmas cliff-hanger. There will be romance, intrigue and tragedy on a grand scale.
Every character will have changes to their storyline in one way or another.
"We are thrilled to be able to have Sol3 Mio appear on the show. We can't say too much but the song they are performing will be the perfect soundtrack to our dramatic end of year."
The last three months of 2015 will be a busy time for Sol3 Mio.
As well as World Cup commitments, an album launch and filming on Shortland Street, Spy thinks the boys may dominate at the Vodafone New Zealand Music Awards in November.
Organisers are tight-lipped on the contenders for this year's' awards but we will know the finalists on October 15.
You don't need to be a rocket scientist to work out that, based on album sales alone, Sol3 Mio will be in the running for an award at the November 19 event. The trio was one of the most popular performers at last year's awards and charmed the audience, traditionally far more comfortable with rock than opera.