Louis Tomlinson's custody was allegedly sparked by his ex-girlfriend's jealousy.

The 24-year-old's court case over his five-month-old son Freddie Reign - which was filed in a bid to get joint physical and legal custody over his child - has reportedly stemmed from Briana Jungwirth's envy towards his new girlfriend Danielle Campbell, which has led to the ongoing ''drama'' between the former couple.

A source close to the mother of one - who gave birth to her child in January this year - told PEOPLE: ''Before Briana got pregnant, she was bragging to friends about how serious she was with Louis. She thought it was going to be a real relationship.

''When Louis started dating Danielle, Briana was upset and that's when the drama started.

''Briana really tried to make the relationship work, and she became jealous when he moved on,''

Although the former One Direction band member was rumoured to have embarked on a romance with Danielle in December, whilst Briana was pregnant, the lothario still underwent his parenting duties and helped provide for his unborn child and the mother to be.

The source explained: ''When she was pregnant he was very supportive and paying for all her medical needs. He bought her a house, but she wanted something bigger.''

Meanwhile, Louis - who reached a temporary custody agreement in February with Briana, which allowed him to see Freddie for several hours at a time with no overnight visits - is allegedly dissatisfied by the settlement and wishes to spend an equal amount of time with his son, who currently lives with Briana in a rented $1 million home in Calabasas, paid for by Louis.

The singer also reportedly currently provides Briana with $15,000 a month but this figure could change when their case goes before a judge, although it is rumoured she has ''gotten greedy'' and has been demanding more money, preventing Louis from visiting Freddie and using the tot to land a better deal.