Charlize Theron has gotten the seal of approval from Sean Penn's daughter.

The 38-year-old actress has been dating Penn, 53, for the past eight months and his daughter Dylan Penn, 23, from his marriage to Robin Wright, is thrilled that her dad has found love with the blonde beauty.

Dylan Penn told Us Weekly: "They're a great couple. They're both very happy and yeah, I love it. They're both extremely strong personalities and they're very intelligent so conversation lasts between them."

While Theron sparked speculation about an engagement when she was spotted wearing a ring on her left hand earlier this week, Dylan Penn insisted she has no idea if they are planning to tie the knot.

She said: "I don't even know. I have no idea."

But asked if she would welcome Theron into the family, an enthusiastic Dylan Penn replied: "Always. Sure, why not? If it's meant to be."

And the model was equally enthusiastic about a sibling for her and brother Hopper Penn, 20.

She enthused: "Always. The more the merrier."