We generalize the Gel’fand-Pinsker model with the setup of a memoryless multiple-access channel where there is a single message source fed to both encoders. Only one of the encoders knows the state of the channel (non-causally), which is also unknown to the receiver. We find an explicit characterization of the capacity of this single-user channel. An explicit characterization of the capacity is also provided for the same channel with causal channel state information. Further, we apply the general formula to the Gaussian case with non-causal channel state information, in which capacity is achievable by a generalized writing-on-dirty-paper scheme.