Order unanimously reversed on the law without costs and motion granted. Memorandum: Supreme Court abused its discretion in denying defendants' motion for leave to serve an amended answer to allege the affirmative defense of exclusivity of workers' compensation as plaintiffs' remedy. Leave to amend shall be freely given absent prejudice or surprise (Fahey v County of Ontario, 44 N.Y.2d 934, 935; see, CPLR 3025 [b]). Defendants have established a prima facie basis for assertion of the proposed defense (see, Hawkins v Genesee Place Corp., 139 A.D.2d 433, 434) and plaintiffs have failed to establish prejudice or surprise if the motion is granted (see, Caceras v Zorbas, 74 N.Y.2d 884, 885; De Forte v Allstate Ins. Co., 66 A.D.2d 1028).