Daniel Craig has said Spectre is "a culmination of all my ambition" since debuting as James Bond in Casino Royale.
Craig, who stars as 007 for the fourth time, told ITV News that he doesn't yet know if he will return as Bond but that the role has been an "incredible blessing".
Director Sam Mendes said he "can't imagine" what the next Bond film will be like, but that 007 could "regenerate" in a new form like Doctor Who.
Mendes, who said he cannot see himself making another Bond film, said the way to follow Spectre would be to "totally change everything".
The future of Craig is in doubt, but Mendes and cast members remained tight-lipped on his future during interviews with ITV News.
Monica Bellucci and villain Christoph Waltz were among those to praise the modernisation of the franchise, which sees the former play the first "mature" Bond girl.
Craig, 47, said there was no timeframe for a decision on the next Bond film and that he just wanted to enjoy the release of Spectre and having some time off.
"The most important thing is audiences now and how they react to it and how they hopefully just enjoy it," he said.
"This is a culmination of all my ambition, as far as I'm concerned, because we've reintroduced the old gags but hopefully they feel fresh and they feel new."
Pressed on whether he would do the next film, Craig said: "I don't know yet, I really don't."
Mendes, who also directed Skyfall, said the challenge was to move the story on and make sure Spectre was not just "another action adventure".
"For me the challenge was could we tell some version of the second half of Bond's childhood, could we tie all four of Daniel's movies together and make it clear that the last three were in some part the work of one other villain," he said. "Could we make him perhaps consider leaving what he does?"
He said that for now he cannot imagine being involved in the next film, but added: "If there's a story to tell worth telling then maybe it's worth doing. Right now I can't imagine where else he (Bond) could go."
If he isn't at the helm, Mendes suggested his successor could start from scratch.
"One of those lovely things about Bond, a bit like Doctor Who, is it can regenerate in a new form, with a new person, a whole new aesthetic," he said.
Bellucci, who plays Lucia Sciarra, described herself as a "Bond woman" and said she liked that audiences can "feel she is 50".
"What I like in the movie is she doesn't look like she's 30 or 40, she really looks 50 and this is the idea of Sam to create this character," the 51-year-old said.
Bellucci and co-star Léa Seydoux said the idea of having a woman direct a Bond film would be interesting.
"Women have another vision of everything," Bellucci said.
Waltz, who stars as villain Franz Oberhauser, agreed that Bond had evolved for the modern world, much like the plot, which focuses on a cyber threat.
He said Bond is "less exploitative" than he used to be and his relationships with women are "more respectful and insightful".
"It's a Bond of our time," said Waltz. "The world has changed and it would be very odd if Bond wouldn't be a child of his world."
Naome Harris's character Moneypenny is more central to the plot in Spectre, as is Ben Wishaw as Q. Harris believes there has been a "massive shift" in the importance of women in Bond films.
She said: "Women are incredibly important in their roles in the Bond movies now which I think is a great development."