GD: So, is there anyone on the list for voice-overs that you’ve wanted, but haven’t been able to get?SM: We just recently started talking about whether or not we can get Christopher Walken, but there’s also things like getting Clay Aiken and Chaka Khan to sing a duet for the summer special. Since we’re both old music fans, we think “We got Chaka Khan – how cool is that?” We called her up and Chaka said yes.DP: We wrote a song that would only be funny if Phineas and Ferb hired Clay Aiken and Chaka Kahn to be their stunt singers and we thought we had written ourselves into a corner because if we don’t get Chaka Kahn and Clay Aiken, we have to rewrite this bit of the episode, but luckily they both said yes.
