Lucas was spotted laughing with director and co-writer JJ Abrams ahead of the film’s premiere in Los Angeles last night.
He revealed: “It’s a film about families and what one generation leaves behind another generation has to deal with.”
He added: “I started off wanting to do a film for young people who were going through adolescence, with mythological themes and spiritual themes.
The plot of the movie is a closely guarded secret but dedicated fans have camped out for days to catch a glimpse of the film’s stars.
They roared as C-3PO and R2D2 walked down the red carpet together and Peter Mayhew – who plays Chewbacca – stepped out of his car with a lightsaber cane.
Harrison Ford – who plays Han Solo – arrived at the premiere in a dark suit while the droid BB-8 rolled along the red carpet.
The seventh instalment in the series reunites Ford with original cast members Carrie Fisher and Mark Hamill.
They are joined by newcomers Daisy Ridley, John Boyega, Oscar Isaac, Adam Driver, Lupita Nyong’o, Domhnall Gleeson and Gwendoline Christie.
Ford, now 73, said making a Star Wars movie now is a far cry from making one in the 1970s.
He said: “In the 70s nobody knew what to anticipate, nobody had seen anything like it. Now we have to live up to what the first films delivered.”