DUBAI, July 28 (Reuters) - Abu Dhabi state investment fund Mubadala has agreed to acquire a 20 percent stake in Investcorp, the Bahrain-based alternative investment firm said in a statement on Thursday.

Mubadala will buy 9.99 percent of Investcorp immediately, and a further 10.01 percent following the necessary regulatory approvals, the statement said without disclosing a value for the transaction.

(Reporting by David French; Editing by Andrew Torchia) ((davidj.french@thomsonreuters.com; +971 4 362 5864; Reuters Messaging: davidj.french.thomsonreuters.com@reuters.net))