The 60-year-old actress discussed her 28-year-old daughter's relationship with Martin, 41, Thursday at the Global Gift Foundation USA Women's Empowerment Luncheon in Los Angeles.
"I adore him!" she told reporters. "But she is very private about her life and I respect that."
Johnson, an actress known for 50 Shades of Grey and its sequels, is the daughter of Griffith and actor Don Johnson. She was first linked to Martin in October, with Us Weekly later reporting the pair were dating.
"They've gotten to know each other really well and are very comfortable with one another. Chris sends Dakota his music to get her opinion," a source said of the Coldplay singer. "It's more than just a fling."
Martin split from Gwyneth Paltrow in March 2014 after 10 years of marriage, and shares 13-year-old daughter Apple and 12-year-old son Moses with the actress. Paltrow is engaged to producer Brad Falchuk, and said this month she's enjoying wedding planning.