Abstract: A method (300) performed in a network node is disclosed for enabling ProSe operation for a wireless device on a non-serving carrier. The network node serves the wireless device on a cell on a serving carrier. The method (300) comprises: determining (310) whether a target cell on a non-serving serving carrier, on which the wireless device is to perform ProSe operation, is known or unknown to the wireless device, and configuring (320, 330) the wireless device with a first gap configuration for the case that the target cell on the non-serving carrier is known to the wireless device, and with a second gap configuration for the case that the target cell on the non-serving carrier is unknown to the wireless device. A method in a wireless device, a network node, a wireless device, computer programs and computer program products are also disclosed.