The DJ admitted he is also "a little bit in denial" about leaving the station after 24 years.
The BBC previously denied evidence of any complaints.
The presenter is standing in for Ken Bruce on his weekday morning show.
The 26-year-old south Londoner is radio's rising star – and she's not finished yet.
As Grimmy hangs up his headphones, the DJ reflects on Breakfast and Brits all-nighters and reveals why he's taking a break from radio.
The DJ has been a mainstay on the station for 17 years.
More of us than ever have turned to the radio to find comfort during the most challenging of years.
"It’s not often I’m speechless but this has left me, quite frankly, gobsmacked."
With four months to go until the big day, Magic has said now is the perfect time to start getting festive.
Choice FM made history in 1990 as Britain's first 24-hour Black music station.