Paris Hilton is loving her new role as a mom.

"My heart feels so full," Hilton, who announced the arrival of her and husband Carter Reum's son Phoenix via surrogacy in January, told "Good Morning America" on Tuesday.

"My little Phoenix is my angel. I'm so obsessed with him," she added. "He is just everything to me."

Hilton, 42, also said she has recently spent time with friend Nicole Richie and her teenage kids, daughter Harlow, 15, and son Sparrow, 13, who she said watch the pair's reality TV show, "The Simple Life," the first season of which premiered 20 years ago this year, and "love it."

"The Simple Life" took both Hilton and Richie out of their glam lives and hilariously had them doing farm work or working in a fast-food restaurant. The show, which ultimately ran for five seasons, catapulted both socialites to fame.

"It's so amazing just how timeless that show is and generation after generation just love it," Hilton said.

These days, Hilton is tapping into a more serious side of herself and reflecting on her life's ups and downs in her new book, "Paris: The Memoir," out now.

"This book was like a diary. I put everything in there, so many really traumatic experiences that I endured, especially as a teenager, and so many just memories I didn't want to remember -- but also a lot of the good, exciting times," she said. "I've lived such an amazing life."

Hilton, who has opened up in recent years about her negative experience in a youth treatment center for troubled teens, called writing the book "so cathartic" and "therapeutic."

As for her advice for her younger self, Hilton said, "I would tell her that you're going to go through a lot in life, but one day you're going to use your voice to help others and make such an impact, so it's going to be worth it."