France-based multinational electric utility GDF Suez has agreed to buy 9% interest in Nabucco Gas Pipeline International from OMV.
The financial terms of the deal were not disclosed.
The Nabucco-West pipeline is a proposed natural gas pipeline from Turkey-Bulgaria border to Austria.
OMV, an Austria-based integrated international oil and gas company, has recently acquired the interest from former shareholder in Nabucco, RWE.
The transaction which is subjected to certain conditions is expected to be completed in the second half of 2013.
OMV chief executive officer Gerhard Roiss said GDF Suez as the new partner for Nabucco West project is a milestone.
"It proves that we are on the right way to provide Europe with more gas and to secure new sources of gas for the future," Roiss added.
"This year we have already seen considerable progress for Nabucco West.
"With this strengthened pan-European partnership we are looking forward to the upcoming decision of the Shah Deniz II consortium concerning their preferred delivery route to Europe."
Following the closing of the deal, Nabucco will be owned by six reliable partners, BEH (Bulgaria), BOTAS (Turkey), FGSZ (Hungary), GDF SUEZ (France), OMV (Austria), and Transgaz (Romania).