Lionel Richie has "no idea" why his grandson is called Sparrow.
The legendary musician, whose daughter Nicole gave birth to her son last week, is waiting to discuss the unusual name choice with his offspring.
He said: "I have no idea where that came from. I will ask her, it is very interesting. With the excitement of the baby, you don't go into the name just yet.
"When I heard it, I thought it was my job just to go 'absolutely' I will ask about Sparrow and she will have a story."
Despite reserving judgement on the new addition's moniker, Lionel is thrilled with the news of the birth.
He is especially pleased with the way Nicole - who also has 20-month-old daughter Harlow with partner Joel Madden - has turned her life around.
Before meeting Joel, Nicole was caught with heroin, and in 2006, she was sentenced to time in jail for driving under the influence (DUI).
Lionel told FOX News: "One thing I love about Nicole is when she makes her mind up to do something, it's done. When Joel came along she found that one person, that partner that she needed to get her into that mode of taking care of herself and paying attention to her lifestyle.
"And then of course when Mouse number one and Mouse number two came along that was it, and I can tell you right now she is a different person."