Paris Hilton is delighted Nicole Richie is pregnant and predicts her pal will be "the best mom ever."

The hotel heiress says she was ecstatic to hear her former "Simple Life" co-star is expecting her first child with Good Charlotte rocker Joel Madden and has high hopes for the family's future.

She tells People.com, "She's really happy. I just got off the phone with her. She's so excited.

"(Nicole and Joel) are really in love. I know she's going to be the best mom ever."