Jeremy - best known for his controversial, eponymous chat show - was met with widespread criticism on Twitter, most notably for a comment he made to one of the show's reporters.
He was heard calling journalist Almeena Ahmed "sweetheart", as she reported on the Pakistan suicide bombings.
But fans didn't stop there, with many more commenting on the switch-up in presenting personnel:
However, there were a few fans pleased to wake up to the sight of Jeremy's face:
Jeremy will co-present the show alongside Kate Garraway until Wednesday, and then again on Monday and Tuesday next week, as Piers and his co-host Susanna Reid enjoy some time off.
ITV News anchor Mark Austin will also co-host the show with Ranvir Singh from Wednesday 6 April to Friday 8.
Speaking of his new role last week, Jeremy said: “‘GMB’ is a fantastic show and I’m really looking forward to stepping into Piers Morgan’s shoes, and even on his toes, over the Easter holidays.
“Along with Kate Garraway, I’ll be helping to wake the nation up and give them the breaking news and entertainment stories of the day over breakfast.”
'Good Morning Britain' airs weekdays from 6am on ITV.