You can watch the moment below:
This morning was Martin's first week on his new job, as host of GMB. And it seems the money saving expert hasn't quite figured out where the studio toilets are, after he disappeared off set during an ad break and didn't make it back in time.
"The truth is people, when you're new to a job and you've been drinking tea since seven o'clock and you can't find the loo in the ad break, you might occasionally be late back to your desk. Move on Susanna!"
Susanna quipped: "TMI Martin, TMI. Look we've got an issue with people leaving the studio on this programme so I'm glad you're back."
Viewers will remember how, shortly before Piers' exit from the breakfast show, he stormed off air after former colleague Alex Beresford challenged him over his comments about Meghan Markle.
Not long after, Piers quit the show, with money saving expert Martin now taking over.
And GMB viewers are loving Martin's presence on the show, with one person tweeting: "What I've seen so far. Martin Lewis is doing a good job. He's a keeper. He's a good speaker, to the point."
Meanwhile another said: "Already Martin is the BEST presenter yet since @piersmorgan left. #MartinLewisToStay."
And one wrote: "I love the show this morning! Martin is a perfect addition to the panel."
A fourth added: "So good to see Martin Lewis hope this is permanent."
Speaking about joining the show, Martin said last week: "For 15 years I loved answering questions on Good Morning Britain, now I'm stoked about getting the chance to ask them.
"While I hope to set the agenda on key consumer issues like scams and the financially excluded, I'm also up for the challenge of spreading my wings on all subjects.
"And when it comes to holding power to account, I always play fair with a straight bat but that doesn't stop me swinging it hard."
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