Gaining mortgage agreement

Hi i have managed to gain an AIP from Nationwide for a joint mortgage with my partner but as i am starting work very soon i don't have any payslips,my mortgage broker has told me that they only need an employers reference which he managed to get,do the underwriters still need payslips to process a final agreement or is he correct in what he has told me? As i am worried sick it is going to get rejected because of this

Thanks people