Louis Tomlinson is set to become a father for the first time.

The One Direction star, who split from long-term girlfriend Eleanor Calder in March, is reportedly ''very excited'' that Los Angeles-based stylist Briana Jungwirth is expecting his baby even though ''they aren't in a relationship.''

A source close to the duo, who were spotted on a number of dates in May, 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 told PEOPLE.com that the 'Story of My Life' hitmaker has vowed to be a ''hands-on dad'' when the baby is born early next year.

The 23-year-old British singer has attended all of Briana's ultrasounds in LA to date and is also looking for new home there to 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.''

The duo introduced their parents to each other earlier this month.