Matthew McConaughey isn't affected by fame: mother

'Interstellar' actor Matthew McConaughey's mother insists he hasn't been affected by fame.

Kay McConaughey claims the 45-year-old actor is the same happy-go-lucky guy he's always been and hasn't changed since carving out a career in Hollywood, reported People magazine.

"As long as I can remember, he's been happy. He's the same thoughtful, kind, happy person he always was. He's just Matthew," Kay said.