Will my e-signature on a contract be enforceable without authority?

Picture this... You are the director of a company that owes a debt of nearly $900,000.00 to one of its suppliers. The supplier will do anything to recover its money, including commencing proceedings against you to enforce a directors' guarantee that affixes your signature electronically. You are confused – the signature on the document is yours, but you did not place it there nor did you expressly authorise anyone else to do so. You acknowledge that ordinarily, your obligations under this directors' guarantee would extend to indemnifying this creditor for the company's debt. But these circumstances are far from ordinary. This gets you thinking... if someone signed electronically on your behalf without your authorisation, is the directors' guarantee still enforceable against you personally?