The Metropolitan Police don't identify suspects who haven't been charged, but said a 46-year-old man was arrested Wednesday night on suspicion of assault and released on bail. No charges have been filed, police said.
Grant's lawyers weren't immediately available for comment.
Photographer Ian Whittaker told the Daily Star tabloid that Grant had kicked him and shouted abuse before hurling the beans at him Tuesday morning.
The newspaper ran photos Wednesday showing the actor holding a plastic tub over his head.
"He lost his temper with the paparazzi who was waiting outside his house," Grant's publicist, Robert Garlock, told The ShowBuzz Thursday.
Garlock said charges are pending. "Basically he was brought in for questioning and the charges are pending, it's now the court's decision. He's back home, he's fine. He confirmed to me that the event happened," Garlock said.
Grant's screen credits include "Four Weddings and a Funeral," "Notting Hill" and "About a Boy."
The British actor appeared in a segment of FOX's reality show "American Idol" on Wednesday in which he lip-synched to a Bee Gee's song.