People magazine reported the "Jack and Diane" singer and the pouty-lipped actress have spent time together on Martha's Vineyard and in New York recently. Mellencamp, who at 59 has a decade on Ryan, last month announced his separation from wife Elaine after 18 years of marriage.
The pair have been spotted having coffee at Espresso Love, one of Ryan's favorite spots on the Vineyard, and grocery shopping at Gourmet Garage in New York's SoHo neighborhood, the mag reported.
"She usually comes in by herself or with her daughter. I thought that was her husband because they seemed for comfortable and familiar with each other, just like an old married couple," one observer says.
Mellencamp has been married three times and has five children, including two sons with Elaine.