Elsewhere, Susanna also asked the PM about the lockdown parties he was fined for, the war in Ukraine, and the cost of living crisis.
But it was the very end of the interview that provided an absolute zinger.
As the PM attempted to get his final few words in, Susanna interrupted him to introduce Lorraine Kelly, whose daily morning programme airs right after GMB.
“Lorraine Kelly is waiting to take up all these issues that you have brought up in this interview,” Susanna told him.
“Who’s Lorraine?” Johnson asked.
Susanna replied: “Who’s Lorraine? Lorraine is a legend.”
But it was Lorraine’s reaction that made everyone’s morning...
“Wow,” Lorraine said following the interview as the show linked back to the presenter in the ITV studio.
“A masterclass in a political interview, excellent stuff,” she added.
Twitter had a lot of thoughts about the “unforgivable” comment....
Lorraine saw the funny side when she referenced the comment in her mid-morning show , asking “why should he know who I am?”.
Asked if Boris Johnson knows who Lorraine is, the PM’s spokesperson told HuffPost UK: “I think as was clear the prime minister was not fully across the ITV daytime lineup this morning. He has a number of issues to deal with.”