Police had been looking for 17-year-old Chelsea O'Donnell who left home in Rockland County, New York, a week earlier, with her therapy dog, a six-month-old black terrier, her mother said.
She had last been seen on August 11.
Chelsea, who reportedly lives with mental illness, was in need of medical attention and had stopped taking her medicine, Rosie told fans through her website and Twitter account. On August 17, she posted on Twitter:
CHELSEA O'DONNELL MISSING https://t.co/5DqsgQoeIB— Rosie (@Rosie) August 18, 2015
But around six hours later, she returned to Twitter to say that Chelsea had been found and was "safe in police custody."
chelsea has been found and is safe in police custody - thank u all for the help and light #missingchildren— Rosie (@Rosie) August 18, 2015
Chelsea was last seen in a black hoodie, dark ripped blue jeans, grey converse sneakers and carrying a black backpack.
The 53-year-old TV personality, who has also acted in films alongside Tom Hanks, was in the headlines most recently over a spat with billionaire White House contender Donald Trump.
Mr Trump attempted to insult her during a Republican candidates' TV debate earlier this month, when questioned about his record on women.