Actor James Van Der Beek has defended his decision to appear in an oddball video by pop star Kesha.

The Dawson's Creek star came under fire from fans for filming a strange cameo appearance in the singer's promo for 2011 track Blow in which he wears a bra and shoots unicorns with laser beams.

However, Van Der Beek is unrepentant about the move, insisting he just wanted to have some fun in his career.

In a chat with fans on, he writes, "The director, Chris Marrs (Chris Marrs Piliero), got the job by pitching his vision to her, and that vision included me with a laser gun shooting unicorns who bled rainbows. I was in a period in my career where I stopped worrying about what people might think and just started saying yes to anything I hadn't done before that sounded like it might be fun."