Your FAA/TC licence is valid for private use on EASA and non-EASA aircraft until 08th April 2015. After this, you will be required to obtain a validation in order to fly an EASA aircraft in EASA states - regardless of it's state of registration. This validation will last for 12 months. Thereafter you will need to obtain an EASA licence.
CAP 804, Section 4, Part Q, Subpart 1 contains more detail. The date in CAP 804 is quoted as 08th April 2014 - this has been superceded by Information Notice 2013/206 which has delayed implementation until 08th April 2015.
http://www.caa.co.uk/docs/33/IN_Defe...n_20122013.pdf
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