Louis Tomlinson's estranged dad has threatened to drop a ''bombshell''.

The One Direction star's 46-year-old father, Troy Austin, hasn't spoken to Louis since they argued during a telephone call three years ago and now he has vowed to shake up his son's life if he continues to ignore him.

A source told the Sunday People newspaper: ''Troy has always wanted to repair that relationship - but if Louis isn't prepared to do so, he's told a few friends he has something which would really throw a grenade into things.

''He sees it as his final shot at getting Louis's attention, and he's said he will drop the bombshell if he feels it's the only option he's got left, even though it would come as a massive shock.

''He knows it could cause another big rift within the family but is starting to feel he has nothing left to lose.''

The threat comes almost a fortnight after it was revealed the 23-year-old musician is set to have a baby with his ex-girlfriend, Briana Jungwirth, with Troy previously revealing he hoped Louis would let him be a part of the tot's life.

He explained: ''I'd like to be involved in my grandchild's life.

''I've missed out on Louis's life and I'd like to make up for that. It's definitely time to heal the rift. Life is too short.''