Mendes unveiled a new cast and souped-up car - an Aston Martin DB 10 - but few other details about the 24th film in the series, that will see Daniel Craig return for his fourth outing as the dapper, martini-drinking agent.
Austrian actor Christoph Waltz would play a leading role, Mendes added, without going into more details. Most commentators assumed the sadistic villain of Quentin Tarantino's "Inglorious Basterds" would play the baddie.
Italian actress Monica Bellucci and French actress Lea Seydoux, who shot to fame in the erotic hit "Blue is the Warmest Colour", would play "Bond girls", Mendes added at a press conference at Pinewood Studios north of London.
In a teaser description of the plot, Sony Pictures Entertainment said in a statement:
"A cryptic message from Bond’s past sends him on a trail to uncover a sinister organisation. While M battles political forces to keep the secret service alive, Bond peels back the layers of deceit to reveal the terrible truth behind SPECTRE."
The title was a clear reference to the global criminal organisation that Bond has battled since the first film in the series, 1962's "Dr No".
SPECTRE infamously stood for the Special Executive for Counter-intelligence, Terrorism, Revenge and Extortion.