Thursday night will be a double whammy for Lauren Conrad.

The former Hills and Laguna Beach star will be at Books & Books Bal Harbour Shops at 6 p.m. to sign two HarperCollins books — a makeup guide, Beauty: Lauren Conrad, and a novel about a reality star in Hollywood called Starstruck. It’s the sequel to her bestseller The Fame Game.

That the books are out at the same time is no coincidence.

“I wasn’t writing them at the same time, just promoting them this way. I prefer to do all the press at once,” she says from Los Angeles.

Conrad is only 26, but her work ethic is off the charts. “If the [editors] give you a deadline, you get it done. If I didn’t have one, I’m not sure I could pull off two books. But yeah, it’s a lot.”

Hard to believe Conrad has no background in writing, just fashion. She learned the process by reading her favorite authors, comedians Tina Fey, Chelsea Handler, Kathy Griffin. “I wanted to write a book that I would want to read,” Conrad explains. “I like a funny book where the voice has a strong presence in the writing.”

Conrad is a seriously busy lady. The designer has two fashion lines — contemporary casual wear Paper Crown and her LC collection for Kohl’s. Add to that green bags XO(Eco) made from recycled plastic, sold on Amazon.

All this work and no play is getting to her. “I’m like a baby. I need a lot of sleep, and I’m not getting it. I’ve had caffeine, but it’s not working!”

She’ll be happy to get to Miami and unwind with some shopping. “I love it there, especially the mannequins you guys have in store windows. They have such huge boobs! It’s always a little shocking. I’m like, wow.”

As for her future plans, they won’t include any stints on reality shows.

“I don’t miss having my life on television, though I did enjoy the creative process and the producing angle. I’m happy now that other people’s lives aren’t affected by my choices. My friends don’t have to sign a release to spend my birthday with me.”