...can you/should you make a reference to the fact that you know each other during the interview or is this bad form.
ie. if this person was your immediate boss a few years ago and knows that you are more than capable of the job you are being interviewed for, can you make a reference to this. If for example you are asked about your strengths could you list them and add something along the lines of " as X can verify"
(thats probably a bad example but my brains a bit fried after stage 1 of the interview process...)