The actress, 37, was paying tribute to her husband, Jesse Plemons, 31, and actress Sofia Coppola, 48, who were both present, when she started wiping tears away from her eyes.
She said: “Jesse, you are my everything, and I never thought I would have a partner that understands me the way that you do. I’m so grateful that you’re both standing by my side.
“Thank you to the Hollywood Chamber of Commerce for this incredible day and inducting me into the Hollywood Walk of Fame.”
She added, “Excuse me, sorry, I can’t look at my family,” and dabbed her eyes while being cheered on by the audience.
Dunst, who has starred in Sam Raimi’s Spider-Man trilogy and Fargo, described how she “never thought” she would be part of Hollywood history when she was a child.
“When I was younger, we stayed at the Highland Gardens Hotel, round the corner from here,” she said. “We would drive around these streets and I always thought the stars were dedicated to the legends of the past.
“I never thought that someday I would even be close to being part of that. I’m so honoured to be here today and a part of Hollywood history.”
It comes after Dunst said she feels she is never nominated for any awards.
In an interview with SiriusXM, she said: “I’ve never been recognised in my industry. I’ve never been nominated for anything. Maybe, like, twice for Golden Globes when I was little and one for Fargo, but I always feel like…maybe they just think I’m the girl from Bring It On.
“I just feel like, what did I do? I’m so chill. Maybe I don’t play the game enough.”
Dunst, who landed her first film role in a Woody Allen-directed movie when she was six, has received more than 60 award nominations but very few are for major accolades. Among them are two Golden Globe nods and one Emmy nomination. Her wins, of which there are more than 30, include Best Actress at Cannes Film Festival and a Critics’ Choice Award.