The Eagles have been without a manager since October 23, when Ian Holloway agreed to leave the club, with a series of possible successors reported to have been in and out of contention.
"I'm happy to carry on doing it until the chairman feels he's found the right person," Millen told Sky Sports News. "We're not in panic stations.
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"I spoke to the chairman [Steve Parish] on Sunday. He asked me to organise this week's training and prepare for the Hull game on Saturday. That's as much as I know at the moment.
"I am pleased that the chairman has showed trust in me. He's not had to rush into filling the position and that's good from my point of view.”
Millen, who has led the Eagles to a draw and two defeats thus far in his three-game tenure, would like to remain at the club whoever the new manager is but admits that he is uncertain of his prospects.
"I'd like to [stay]," he remarked. "I know how it works, some managers like to bring their own people in. I love working at Crystal Palace and am enjoying my time here.
"When someone comes in I'm sure I'll sit down with the chairman and the new manager and discuss the future."