The soul singer – whose adopted daughter Nicole Richie gave birth to his first grandchild Harlow Kate Winter Madden in January – has adapted the traditional title to reflect his youthful attitude.
The 58-year-old star said: “I went to Nicole and said, ‘Grandpa, how does that sound? Does that fit me?’ She said, ‘Dad, that sounds old.’ So I kind of searched out. ‘G-Pa’ sounds a lot better.”
Grandma Brenda Richie – who legally adopted Nicole when she was nine years old with Lionel, before their marriage ended in divorce in 1993 – has revealed baby Harlow has already started talking.
Speaking at the ASCAP Pop Awards in Hollywood, she explained: “The other day I was holding her, and Harlow said, ‘Hi!’ I said, ‘Nicole, did you hear that?’ Nicole said, ‘I don’t think she knew what she was saying!’
“Nicole talks to Harlow constantly, and she tries to answer back!”
Brenda also joked Nicole – who is engaged to Good Charlotte rocker Joel Madden – can’t bear to be parted from the family’s latest addition.
She added: “I’m lucky if I get to see the baby. Nicole loves being with that baby!”
Nicole, 26, agreed she can’t get enough of her bundle of joy.
She gushed: “Motherhood is definitely like nothing I could have imagined. It’s beyond amazing and my family has been supportive.”