There are multiple artists called Heidi:
1) Heidi is a danish sing and songwriter, know form the Danish edition of X-Factor.
2) Heidi is Canadian born, Berlin based DJ and producer.
3) Heidi is a Japanese rock band.
4) Heidi Janku is a Czech pop singer.
5) Heidi is a UK based R'n'B singer.
6) Heidi is a Finnish pop singer.
7) Heidi was a Boston-LA rock band.