Joinder of the proposed new counterclaim defendant is warranted by the relation back doctrine of CPLR 203 (b) and (f) ( see, Buran v. Coupal, 87 N.Y.2d 173, 177-182). Unity of interest between plaintiff and the proposed new party is demonstrated by plaintiff's president's admission at his deposition that he is the owner of both plaintiff and the proposed new party, and that he received the invoices relating to the alleged agreement between defendant and the proposed new party. It also appears that defendant would have joined the new party at a much earlier time had it known of the relationship between plaintiff and the new party, which was first revealed by plaintiff's president only at his deposition conducted five years after the service of plaintiff's first reply to defendant's answer. Finally, the original pleadings and the proposed amended answer relate to the same series of transactions and occurrences.
Concur — Ellerin, J. P., Wallach, Rubin, Tom and Saxe, JJ.