Speaking to TV Week, the Molly actor revealed that he does not plan on having children any time soon as he prepares to look after his nephews due to his sister Connie's seven-year battle with breast cancer.
"I've had kids in my life my whole life," the 39-year-old revealed. "I don't really need to squeeze my own out to have them."
Johnson has two nephews, Willoughby, 10, and Hamilton, 9.
"Connie's got some pretty important jobs for me when it comes to her kids once she's gone," the star added.
"I've got to make sure I get everything right."