Matthew Mcconaughey's mum won't let anyone call him Matt.

The 47-year-old actor won't answer to the popular shortened version of his moniker after his mother - who was also his teacher when he was in kindergarten - once ''got mad'' at him for letting a friend at school use a nickname.

Asked by Jimmy Kimmel on his talk show 'Jimmy Kimmel Live!' if he answers to Matt or Matthew, the 'Gold' star said: ''It's always been Matthew, and for good reason. I tell you mum got mad when I got called Matt.

''I was in kindergarten and my mum's a kindergarten teacher, and my buddy John comes up to me and is like 'Hey Matt do you wanna go play on the monkey bars?' and I ran out and said 'Yeah' and halfway to the monkey bars I feel this hand on my shoulder and I get slammed to the ground and I look up and it's my mother in my face.

''She's like 'What are you doing?' and I was like 'I'm going to play on the monkey bars with John.' She goes 'Who is?' I said 'I am,' she said 'What's your name?' I said 'Matthew,' she goes 'Don't you ever answer to Matt again, I named you Matthew from the bible.'''

And the 'Dallas Buyers Club' star says he now steers clear of the shortened format for fear of encountering his mother.

He added: ''If anyone calls me Matt today, I don't look. My mum could be there at any corner. I know they don't know me well.''

Matthew - whose brother is nicknamed Rooster - also noted that Matt seems to be the only moniker his mother doesn't approve of.

He said: ''Rooster is fine, son of a b***h is fine, but Matt? No.''