Louis Tomlinson, Baby Mama -- Custody Fight Over His Girlfriend

Louis Tomlinson is going to court for joint custody because he claims his baby mama is keeping him from their child because she hates his girlfriend, but she says the GF poses a security risk to the kid.

TMZ broke the story, the One Direction singer is now asking a judge to award him joint custody and equal access to 5-month-old Freddie, because recently she's been denying him access to the infant.

We're told Louis chalks the whole thing up to jealously. There have been lots of pics posted of him and Danielle Campbell, and he says the photos send her into a rage.

Louis says he and baby mama Briana Jungwirth have actually gotten along until recently and he was seeing the baby all the time, but things have now taken a turn for the worse.

As for Briana, we're told she says it's annoying that when Louis has the baby, he'll come back home smelling like perfume. But Briana's real problem ... she believes Danielle may be nothing more than a crazed fan who now knows her home address and gate security code.