Very much so. It may be the lubricant alongside you, of course.

Joking apart, if you're not doing any kind of warmup your voice won't have settled into singing "mode". When we sing, we process the words from the left hemisphere through the right-hemisphere, adding the musicality, whereas when we speak it goes straight to the voice. I have hangups with the second I don't have with the first, for instance. It takes a moment or two to find one's bearings, that's all, like Leeneia says. She warms up beforehand, you when you're singing. That's all.