Ridley Scott is known for being pretty outspoken. He's not happy historians and French people are calling him out for his portrayal of Napoleon, but apparently not even other directors are safe from his tongue lashings.
In a recent interview with The Times, Ridley Scott recalled the time when Stanley Kubrick called him following the release of Alien. "He said: 'It's Stanley Kubrick.' I said: 'Fuck off!' He said 'No, it's Stanley Kubrick.' He said 'I watched Alien, how did you bring the creature out the guy's chest?'"
It sounds like Scott told Kubrick to "fuck off" more out of surprise than anything else. It certainly would be a shock to get a call from one of the greatest directors of the time out of the blue. It also seems perfectly fitting for Kubrick for him to ask immediately how Scott pulled off some movie magic.