These aren't your average ladies who lunch.

Moms to two of the most famous teenagers in the world, Tish Cyrus and Pattie Mallette (who gave birth to Justin Bieber** eighteen years ago) surely had plenty to talk about when the grabbed a meal together in Calabasas, Calif. Nov. 15.

The two women were spotted leaving the popular Corner Bakery & Cafe eatery Thursday afternoon. Cyrus, whose daughter Miley is set to tie the knot with Liam Hemsworth, even toted a copy of Mallette's new memoir, Nowhere But Up: The Story of Justin Bieber's Mom, on her way out of the restaurant. (Cyrus is also mom to Braison and Noah with country star hubby Billy Ray Cyrus; Bieber, meanwhile, is Mallette's only child.)

During a visit to Us Weekly's New York offices last month, Mallette imparted some of her motherly wisdom on Us, too.

"I've been through so much pain in my life that I've just always taught [Justin], don't learn the hard way," Mallette, 37, shared during a discussion of her memoir, which chronicles her struggles as a teenage mom. "Learn from my mistakes."

HOTOS: Miley's hair evolution**

"He started hearing my story when he was about 12 years old," Mallette added. "I just hope that he's able to use some of that instead of going through things the hard way."

This article originally appeared on Usmagazine.com: Justin Bieber's Mom Pattie Mallette, Miley Cyrus' Mom Tish Do Lunch!