No, he won't be the mother.
But How I Met Your Mother has cast Emmy Award winner John Lithgow in a key role: he'll appear on the sitcom as Barney's father!
Rumors about Jerome Whitaker have run rampant throughout this show's run. While there's no word yet on how or when he will enter his son's world, Michael Ausiello confirms that Lithgow has landed the part.
The veteran actor last recurred on Dexter, portraying The Trinity Killer on what most considered to be that drama's best season.