Parse a json that contain json string

I have a json which has another json inside it. But it is inside double quotes due to this it is given me a parsing error. Is there any way to parse this json other than useing gsub to replage double quote..

obj={Name:"{"FirstName":"Douglas","LastName":"Crockford"}"}

I want it like this

{Name:{FirstName:"Douglas",LastName:"Crockford"}}

Is there any way to achieve this using Ruby