Incoming CEO Fidji Simo, who until last month was head of the Facebook App, officially took over Instacart’s top job on Monday. Her first public move: hiring her longtime colleague Carolyn Everson, Facebook’s former global ad chief, as her new company’s president.

Everson, a leading advertising executive who resigned from Facebook in June, will start at Instacart on Sept. 7, the grocery-delivery startup said on Wednesday. Current president Nilam Ganenthiran will become a strategic adviser to Simo, who is succeeding founder Apoorva Mehta as Instacart comes off a massive pandemic growth spurt and prepares for an expected initial public offering. The San Francisco company recorded $1.5 billion in revenue last year and is privately valued at $39 billion, but needs to fend off fierce competition from other delivery services and figure out new growth strategies, now that post-lockdown customers are returning to in-person shopping.

Simo and her new president worked together at Facebook for about a decade “and have become good friends,” Everson wrote on LinkedIn in May. Earlier this summer, the two women announced their departures from the social media giant within weeks of each other. Now Everson will report directly to Simo and assume responsibility for an expansive portfolio that includes Instacart’s retail, business development, and advertising operations, as well as its teams devoted to people, policy and government affairs, legal, partnerships, Instacart Pickup, and care.

“Carolyn’s an industry legend, best known for cultivating strong, trusted relationships,” Simo said in a press release, adding that Instacart is tapping Everson to strengthen those relationships with more than 600 retail partners and thousands of advertisers.

The two executives are reshaping an Instacart leadership team that already includes another former Facebook colleague, chief operating officer Asha Sharma. She moved from her role as Facebook vice president of product in February, a month after Simo first joined Instacart’s board. And the Facebook hiring spree goes beyond the C-suite: Last month, The Information reported that Instacart has hired at least 55 engineers, product managers, recruiters, designers, and data scientists from Facebook so far this year. (Instacart downplays the suggestion that it has targeted one particular tech giant for poaching; a company spokesperson says that within the past 12 months, the company has hired “an equal number of people from Amazon, Google, and Facebook.”)

Notably, Instacart’s new CEO, COO, and president are also three female former Facebook executives. Women now account for 55% of Instacart’s nine-person senior leadership team—a rarity in Silicon Valley and among IPO-bound unicorns.  

Instacart’s gender-diversity gain appears to be Facebook’s ongoing loss. Mark Zuckerberg’s enormous but controversy-wreathed company is facing questions about the future of its senior women, as Fortune reported last month. Simo’s departure, announced a month after Everson’s resignation, came on the same day that the New York Times published an extensive report describing how chief operating officer Sheryl Sandberg’s influence has waned in the past half-decade. And earlier this year, Deborah Liu left her role as Facebook vice president of app commerce to become CEO of Ancestry.com.

Facebook chief diversity officer Maxine Williams last month downplayed the significance of these departures, telling CNBC, “We’re sad to see them go,” but “the experience of being at Facebook gives people the opportunity to do so many other things.” According to Facebook’s 2021 diversity report, based on data pulled before Simo’s exit, women held 35.5% of leadership roles at the company, a slight increase from 34.2% in 2020.

A Facebook spokesperson told Fortune Wednesday, “We wish Carolyn the best as she moves into this new chapter.”