A method in a network node for assisting a first user equipment in interference mitigation. The network node is comprised in a cellular communications network. The cellular communications network further comprises the first user equipment and a second user equipment. The second user equipment causes interference to the first user equipment when at least one of the first user equipment and second user equipment communicate by using Device-to-Device communication. The network node obtains information about the receiver of the first user equipment. The network node then determines one or more parameters required by the first user equipment for mitigating the interference. The parameters relate to the obtained information and to the interfering second user equipment. The network node then sends the one or more parameters to the first user equipment thereby assisting the first user equipment to mitigate interference caused by the second user equipment.