Will Smith used to choose films based on his need "to be biggest movie star" rather than for their artistic merit.

The Ali star successfully made the tricky transition from rapper to television star to blockbuster lead thanks to roles in Independence Day, Bad Boys and Men in Black. But he suffered a slump in the late '90s, which he blames on his earlier success making him so hungry "to win" that he picked the wrong projects as he was more focused on money and box office credentials over great storylines.

"I had so much success that I started to taste global blood and my focus shifted from my artistry to winning," he said during a talk at Cannes Lions advertising festival on Tuesday (21Jun16), according to the Hollywood Reporter.

"I wanted to win and be the biggest movie star, and what happened was there was a lag - around Wild Wild West time - I found myself promoting something because I wanted to win versus promoting something because I believed in it."

He added that the late boxing legend Muhammad Ali, who he portrayed in biopic Ali, was an inspiration to him because he never compromised his values for the sake of money or recognition.

According to the website, Will often cited Wild Wild West at the event at a personal lowpoint when discussing movie marketing. The 1999 film, which co-starred Kevin Kline, was a critical and box office disappointment, making only $222 million worldwide against a $170 million budget.

He told the audience that marketing can no longer hide a terrible film because cinemagoers will immediately take to social media and spread the word.

"Smoke and mirrors in marketing and sales is over. People are going to know really quickly and globally whether a product keeps its promises," he said. "Back in the '80s and '90s you had a piece of c**p movie you put a trailer with a lot of explosions and it was Wednesday before people knew your movie was s**t... But now what happens is 10 minutes into the movie, people are tweeting ‘This is s**t, go see Vin Diesel'."