A method performed by a wireless device for performing an uplink control channel transmission in a serving cell in a wireless communications network is provided. The wireless device is configured with a set of serving cell(s) in the wireless communications network. First, the wireless device determines a number of serving cells of the set of serving cell(s) that are relevant to consider when performing the uplink control channel transmission in the serving cell. Secondly, the wireless device selects an uplink control channel format from a set of uplink control channel formats for uplink control channel transmissions based on the determined number of serving cells. Then, the wireless device performs the uplink control channel transmission in the serving cell using the selected uplink control channel format. A wireless device for performing an uplink control channel transmission in a serving cell in a wireless communications network is also provided.