the new A310MRTT

Hi everyone! I have a question about the new A310 Multi-role transport tanker, that wil enter service in Luftwaffe in May this year. Are the planes new-built, or they are gonna be converted from a passenger A310 to transport tankers? Thanks in advance!
P.S. And if someone knows something interesting regarding this topic it will be wellcome. Also if someone has seen or has flown the first on A310MRTT.