The bassist, who has been with the rockers since 2010, invited the Sopranos actress onstage with her children during a gig at the Trump Taj Mahal Casino in Atlantic City, New Jersey.
Devin, who was holding her son, said to de Matteo, "I've been in love with you since the day I met you and I will for the rest of my life and I hope that you'll marry me. I have two questions. 1: Will you make sweet passionate love to me for the rest of my life?... and 2: will you marry me please?"
The actress agreed and told the audience, "I'm a (I will) marry this motherf**ker."
De Matteo was previously engaged to musician Shooter Jennings, who also popped the question onstage in 2009. They have two children together.