MILAN, April 26 (Reuters) - Italian defense group Leonardo said on Tuesday its U.S. unit DRS had agreed to sell its entire stake in Advanced Acoustic Concepts (AAC), its 50-50 joint venture (JV) with a subsidiary of French peer Thales .

In a separate statement, Thales said that under the definitive deal, which is expected to close in the second half of the year, its unit Thales Defense & Security (TDSI) would acquire DRS's stake and gain full ownership of AAC, which operates in the fields of advanced sonar, training and knowledge management systems.

The consideration for DRS' stake in the JV should amount to around 50 million euros ($53.41 million), according to two sources with knowledge of the matter.

Leonardo also confirmed its guidance for a 2022 group net debt of about 3.1 billion euros.

The divestiture follows last month's DRS sale of its satellite communications business GES to SES for $450 million, gross of taxes, as Leonardo rationalizes its asset portfolio to focus on core activities such as electronics for defense and helicopters.

"The transaction is another step forward in the execution of our industrial plan, we are continuing to focus on our core business," Leonardo Chief Executive Alessandro Profumo said, adding that the deal marked a "further step in the process of refocusing DRS business portfolio."

($1 = 0.9349 euros) (Reporting by Federico Maccioni and Francesca Landini, Editing by Louise Heavens)