Hollywood star Tom Cruise has clashed onscreen with US TV host Matt Lauer after he questioned the actor's stance against anti-depressant drugs.
Cruise caused controversy when he publicly criticised fellow actor Shields
It follows Cruise's recent criticism of Brooke Shields, who has admitted taking drugs for post-natal depression.
In a heated exchange, Cruise - who was promoting his film War of the Worlds - told the NBC presenter to "be more responsible" when discussing the drugs.
Cruise follows the Scientology movement which is against psychiatric medicine.
Defending his remarks, the actor took exception when Lauer suggested some people could benefit from drugs such as Ritalin, which is prescribed to children with attention deficit hyperactivity disorder (ADHD).
"Matt. Matt. Matt, you don't even - you're glib. You don't even know what Ritalin is," he said.
"If you start talking about chemical inbalance, you have to evaluate and read the research papers on how they came up with these theories, Matt, okay? That's what I've done.
"Psychiatry is a pseudo science," he said.
"She [Brooke Shields] doesn't understand the history of psychiatry. She doesn't understand in the same way that you don't understand it, Matt.
"You don't know the history of psychiatry. I do," he added.
When Lauer said he had known people who had been helped by anti-depressants, Cruise accused him of irresponsibly advocating drugs about which he knew little on national television.
"Just knowing people who are on Ritalin isn't enough. You should be a little more responsible," he said.
Cruise announced his engagement to Katie Holmes at a press conference in Paris on 17 June, and his public declarations of love for the actress have been a feature of his work promoting War of the Worlds.