Stewart complained during a talk at the Montclair Film Festival in New Jersey last week that he would never invite Grant back because he was "a big pain in the ass" during a 2009 interview.
Grant admitted via Twitter Friday that Stewart was right.
"Turns out my inner crab got the better of me with TV producer in 09," Grant tweeted. "Unforgivable. J Stewart correct to give me kicking."
Grant's films include "Love Actually," "Bridget Jones's Diary," "Four Weddings and a Funeral" and "Sense and Sensibility." He appeared on "The Daily Show" to promote his movie "Did You Hear About the Morgans?"