Louis Tomlinson is to become a father.

The One Direction star, who split from long-term girlfriend Eleanor Calder earlier this year, is reportedly ''very excited'' about expecting a baby with Los Angeles-based stylist Briana Jungwirth despite the fact ''they aren't in a relationship.''

A source said: ''Louis is happy and very excited about becoming a dad and he thinks Briana will be an amazing mother. It was a surprise at first, but he and Briana are very, very close friends and this has brought them even closer.''

The insider also revealed that the 'Night Changes' hitmaker - who was seen on numerous dates with Louis following his split from Eleanor in March - has promised he will be a ''hands-on dad'' when the baby is born in the new year.

The 23-year-old singer is said to have attended all of Briana's ultrasounds in Los Angeles and is even looking for a home there so he can help raise the baby.

The source added: ''Louis and Briana care about each other very much and have spent a lot of time together privately over the last few months.

''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.

''Briana is a really lovely girl; she's absolutely not interested in Louis' fame. She's very private and most of the time they spend together is out of the public eye, just hanging out with their friends.''