The president has branded the deal the "worst" ever backed by the United States and reimposing sanctions would effectively torpedo the global alliance behind the deal. 'Cause that's what we're talking about.
Trump has until May 12 to decide whether to reintroduce US sanctions on Iran, which would deal a heavy blow to the agreement. The Foreign Secretary, who followed TV medic Dr Oz on the show, urged Mr Trump not to "throw the baby out with the bathwater" and work with him to improve the deal.
"If you do that you have to answer the question what next?"
Britain, France and Germany remain committed to the accord and, in an effort to address USA complaints, want to open talks on Iran's ballistic missile program, its nuclear activities beyond 2025 - when pivotal provisions of the deal expire - and its role in the wars in Syria and Yemen.
"Is that really a realistic possibility?"More news: New York Yankees & Boston Red Sox to play each other in London
More news: Gmail will soon be writing entire emails for you
More news: Bombing at mosque in Afghanistan kills 12, wounds 30+
According to Johnson, the USA withdrawal from the agreement would be a big mistake, in the case of unilateral withdrawal of Americans will benefit only Iran.
Trump told reporters that he was only interested in a "great deal" for peace with North Korea.
The decision to award Mr Obama the prize in 2009 just a short time after he entered the White House proved controversial.
"We are determined to save this deal because this accord safeguards against nuclear proliferation and is the right way to stop Iran getting a nuclear weapon", French Foreign Minister Jean-Yves Le Drian said during a press conference.
A historic agreement on the Iranian nuclear programme was taken on 15 July 2015.
Mr Johnson has previously accused Mr Trump of talking "nonsense" - and once quipped that he wouldn't visit parts of NY for fear of encountering him.