The second, B part of the palace is to be unveiled on Friday, with an official ceremony marking the completion to be held on July 6, the Day of Statehood.
The reconstructed palace with a total area of 13,500 square meters houses a national museum that contains 0.5 million archaeological exhibits of unique Lithuanian heritage.
Construction work started back in 2002 and the first part opened to visitors in July 2013.
The construction project has cost over 100 million euros in total.
The Palace of the Grand Dukes consists of four buildings and a closed courtyard and was built over the remaining ruins of the original palace, which was demolished 200 years ago.