The invention refers to a sequential combustor arrangement including a first burner, a first combustion chamber, a dilution burner for admixing a dilution gas and a second fuel via a dilution-gas-fuel-admixer to the first combustor combustion products. The dilution-gas-fuel-admixer has at least one streamlined body which is arranged in the dilution burner for introducing the at least one second fuel into the dilution burner through at least one fuel nozzle, and which has a streamlined cross-sectional profile and which extends with a longitudinal direction perpendicularly or at an inclination to a main flow direction prevailing in the dilution burner. The streamlined body includes a dilution gas opening for admixing dilution gas into the first combustor combustion products upstream of the at least one fuel nozzle. The disclosure further refers to a method for operating a gas turbine with such a sequential combustor arrangement.