But the former Liverpool boss insists there is nothing to worry about and it is only a matter of time before he puts pen to paper.
Houllier finally takes charge of Villa for the first time in Wednesday's Carling Cup clash with Blackburn after agreeing to become Martin O'Neill's successor nearly two weeks ago.
When asked if he had signed the contract, Houllier said: "No, not yet but it is okay.
"The word is more important than the rest. You mean physically? No, but don't be worried.
"This is not important - I think at Liverpool, I didn't sign until November or December."
Source: PA
Source: PA