The "Piano Man" singer, 65, and girlfriend Alexis Roderick
are expecting their first child together this summer, his
rep confirms to PEOPLE
The baby on the way - a source tells PEOPLE it's a girl! - will be Joel's second child.
has one daughter, singer/songwriter Alexa Ray, 29, from his
previous marriage to supermodel Christie Brinkley.
Joel and Roderick
, 33 - an accomplished equestrian and a former Morgan Stanley
executive - have been together since 2009.
Im not making any morality calls on Ms Roderick
, but hey...you are young enough to be his
they should start building a Breakfast at Tiffany's themed nursery for Billy Joel's second daughter which she'll be named her Madison Rosalind Nyman Joel and they should hire Alexis' mom Mrs. Roderick
to be invited to her baby shower