The UK rapper spent the day at United's Carrington training complex and met Jose Mourinho's squad before dropping in on Carrick's media duties.
Stormzy may be making waves in the musical world at present but he confessed to being "starstruck" by the 35-year-old's presence.
Carrick is set to stage his testimonial at Old Trafford on June 4 - the day after the Champions League final.
The former England international, who joined United from Spurs in 2006, has asked all of United's 2008 Champions League-winning team to take part.
But the veteran's long-term future is still uncertain with his contract set to expire at the end of the season.
"Right now, there is nothing to report," he told the BBC.
Meanwhile, Stormzy is no stranger to United collaborations, having helped announce Paul Pogba's return to Old Trafford last summer.