But the plan seems to be moving along, as McConaughey told ET during the press junket, "His father's 91, my mother's 88. Yeah, why not?"
"Next week, they're supposed to meet, and we probably won't see them for the rest of the night," he quipped.
McConaughey's dad Jim McConaughey -- who passed in 1992 -- had married McCabe three times, welcoming son Matthew after the third nuptial. Grant's mother, Finvola, died from pancreatic cancer in 2001 at the age of 67.
Meanwhile, McConaughey has been together with his partner Camila Alves since 2006, marrying in 2012, and sharing their three children Levi, Vida and Livingston.
Grant -- once referred to as a lifelong bachelor -- finally settled down with wife Anna Eberstein, marrying in 2018. They share three children. He also co-parents two children with former partner Tinglan Hong.
McConaughey and Grant share the screen in Guy Ritchie's "The Gentlemen," an action comedy about the underbelly of the marijuana business, which also co-stars Charlie Hunnam, Henry Golding, Michelle Dockery, Jeremy Strong, Eddie Marsan and Colin Farrell.