Seal wants to adopt Heidi Klum's daughter before Christmas.
The 'Kiss From A Rose' singer is keen to take legal guardianship of five-year-old Leni - his wife's daughter from her relationship with Formula One boss Flavio Briatore - and has already begun the legal proceedings.
Heidi's father Guenther said: "Heidi, Seal and the kids have always been a happy family - in everyday life and in their hearts. Then they should also be happy on paper."
Seal - who has three children with Heidi, Henry, four, Johan, three, and six-week-old Lou - has been given the go-ahead by Flavio to adopt Leni.
Seal has always classed Leni as his own daughter, even though he did not father her, and he got together with Heidi while she was still pregnant with Leni.
Speaking soon after Henry's birth, Seal said: "Leni is my first child. Just like Henry I saw her take shape and move in Heidi's body. And I was present at her birth, too.
"Leni is my daughter and Henry is my son. I am happy to have two healthy children and that Henry will soon be saying papa to me just like Leni does already."