The letter ‘z’ (last letter of the alphabet) can be pronounced:
/zed/ (British English)
/zi/ (American English)
That’s why we have two different versions of the famous alphabet song. It’s true that the rhyme goes better with /zi/, but I can make it sound good too with /zed/ the way I sing it.
This is the version with /zi/.
And this is the version with /zed/.