Louis Tomlinson's impending fatherhood is already enough to shock One Directioners but a bigger "bombshell" might soon be dropped by his father, Troy Austin.

Louis Tomlinson's dad is allegedly hurt that his son still hasn't patched things up with him. For this reason, he will reportedly resort to spilling a family secret which will "throw a grenade into things."

"He knows it could cause another big rift within the family but is starting to feel he has nothing left to lose," said the insider to Mirror.

Louis Tomlinson's father separated with the British crooner's mom when he was five years old. The "Night Changes" crooner then took the last name of his stepfather.

The 1D member last spoke to his biological dad three years ago but the phone call didn't end well.

Apart from hoping to reconcile with his son, Troy Austin reportedly wants to have a relationship with his grandchild.

"I'd like to be involved in my grandchild's life. I've missed out on Louis' life and I'd like to make up for that. It's definitely time to heal the rift. Life's too short," he told in an interview with Mirror.

"I'm sure he will be a great dad if he commits to it fully. I'd hate to think of him having the sort of relationship with his child that we have had," said Louis Tomlinson's estranged father.

While the Doncaster-born singer's camp remains hush about the issue, it appears that Louis Tomlinson has found a father figure in Simon Cowell.

The music mogul said he wants the "Best Song Ever" hit maker to "man up" now that he'll become a father.

The producer also told The Sun that he advised Louis Tomlinson to not be too hard on himself because he's "in a position to be able to look after the baby and not worry about too much else."