When an Music artist's song or record Ironicly describes the mental state or position the singer is in. Amy Whinehouse's Rehab and britney's Lucky is the best example of this.
A classic example of Spears Irony:
And they say
She's so lucky
She's a star
But she cry cry cries in her lonely heart
Thinking, if theres nothing missing in my life
Then why do these tears come at night?
The course of Britney's Lucky