Matthew McConaughey Reveals the Very Good Reason He Never Goes by 'Matt' -- See What He Said!

The 'Gold' star knows: Always listen to your mama!

Matthew McConaughey learned from a very young age to listen to his mother.

The Gold star appeared on Tuesday's Jimmy Kimmel Show, where he shared that he doesn't answer to Matt, and revealed why.

EXCLUSIVE: Matthew McConaughey Calls 'Gold' Character a Career Favorite, Praises Wife Camila Alves for Support

"It's always been Matthew, for good reason," the 47-year-old actor explained. "I was in kindergarten -- my mom's a kindergarten teacher -- my buddy, John Griffith, says, 'Hey, Matt! Wanna go play out on the monkey bars?' I ran out and say, 'Yeah.' And all of a sudden I feel this hand on my shoulder."

That hand was his mother!

"She goes, 'Don't you ever answer to Matt again. I named you Matthew from the Bible,'" he shared. "So if anyone calls me Matt today... Mom, could be there, in any corner."

MORE: Matthew McConaughey Says His Wife Misses the Extra Pounds He Put on for 'Gold' Role

Can't really have a much better reason than that!

Watch Matthew's hilarious story below.

WATCH: Matthew McConaughey Turns 47! 13 Times He Was Our Spirit Animal

Meanwhile, McConaughey also opened up about his nearly 50-pound weight gain on Kimmel, which he also expanded on to ET recently.

Watch the video below to see what he said.

Gold arrives in theaters on Jan. 27.