Mary, in the corner shop,
Seduced herself with an alco-pop.
The top came off, the pop ran wild.
She gave birth to a bright blue child.
They called the bastard Wicked, (WKD)
They called the bastard Wicked,
They called the bastard Wicked.
'cos that was the name of the pop
Pop pop.

Mary on the banks 'o' Clyde
Seduced herself with a can inside.
The ring-pull broke, the brew ran wild.
She gave birth to a rust-red child.
They called the bastard Iain,*
They called the bastard Iain,
They called the bastard Iain,
'cos that was the name of the brew.
Irn Bru!

In order to sound like 'Irn Bru' it may be necessary to use the Welsh version of the name: Ieuan, but the drink, and the Clyde, make it particularly Scottish.