The 23-year-old is allegedly expecting a child with LA-based photographer Briana Jungwirth.
A source told People magazine: "Louis is happy and very excited about becoming a dad and thinks Briana will be ana amazing mother.
"It was a surprise at first, but he and Briana are very, very, close friends and this has brought them even closer."
According to the reports, Louis and Briana are no longer a couple, but they are planning to raise the baby together.
The source continued: "They are both really happy and although they aren't in a relationship, their friendship is extremely strong and they are both really excited about the baby.
"It's early days and Briana and the baby's health are the most important things right now."
Louis and Briana are said to have enjoyed a few dates around May, after his split from long-term girlfriend Eleanor Calder.
The One Direction singer is said to have been supporting Briana through her pregnancy, and flew out to America to be with her for the first scan.
Louis has yet to comment on the reports.