The 50-year-old actor played tour guide to the likes of Nicolas Cage, Chloe Grace Moretz and Aaron Johnson and kept his guests entertained by performing a rendition of The Proclaimers' I'm Gonna Be (500 Miles) as they sailed down the river, reported Sun online.
"He didn't get a single point of interest right, but his version of London's history was much more entertaining," a source said.
Carrey was celebrating landing the role of Colonel Stars in the sequel to 2010's wacky superhero comedy after expressing his love of the original "Kick-Ass" film by Matthew Vaughn.