Why Lizzie Marvelly might struggle singing the national anthem for the All Blacks tomorrow

Lizzie Marvelly says she will "give it my all" singing the anthem before the All Blacks game tomorrow - despite coming down with a hellish cold.

The Auckland-based singer is due to sing the New Zealand national anthem before the game at Eden Park, which sees the All Blacks take on Wales for the first in a three-test series.

But Marvelly tweeted a photo showing how much medication she was taking - including Strepsils and Vicks Vapodrops - to help overcome her illness.

The collection of medicines also included nasal sprays and "ear nose and throat tonic".

In subsequent tweets, she said she was taking "the strongest s*** I can lay my hands on," and, "Thank God they don't drug test the anthem-singers".

As long as she doesn't do anything to end up on a list like this, she should be fine.