By MOLLY NAGLE and JUSTIN GOMEZ, ABC News

(WASHINGTON) — President-elect Joe Biden is expected to name former 2020 rival and South Bend Mayor, Pete Buttigieg to head the Department of Transportation, sources familiar with the transition told ABC News Tuesday.

If confirmed, Buttigieg would bring new diversity to the administration Biden has promised will “look like America,” as the first openly gay Cabinet secretary approved by the U.S. Senate to serve in U.S. history.

Buttigieg, at age 38, would also be the youngest person nominated to Biden’s Cabinet — bringing the average age of Biden’s Cabinet and Cabinet-level appointees down from 61 to 59.

Buttigieg, seen as a rising star in the Democratic Party following his quick ascent during the 2020 primary, is also the first formal rival Biden has picked to join his administration since he announced Kamala Harris as his running mate in August.

Buttigieg endorsed Biden in March shortly after ending his own presidential campaign, and both he and his husband, Chasten Buttigieg took an active role during the General Election, campaigning on behalf of Biden.

Biden spoke highly of Buttigieg following the former mayor’s endorsement, saying he reminded Biden of his late son, Beau.

“I don’t think I’ve ever done this before, but he reminds me of my son Beau. And I know to — that may not mean much to most people, but to me, it’s the highest compliment I can give any man or woman,” Biden said of Buttigieg in March.

Though Buttigieg would push forward Biden’s transportation initiatives, the former mayor released his own $1 trillion infrastructure plan in January that included improvements to a range of the country’s transportation infrastructure. Its detailed plans to give more power to local communities, called for upgrades to roads and public transportation and also highlighted road safety with a national Vision Zero goal.

Biden has laid out an ambitious infrastructure plan for his administration that Buttigieg would likely have a significant role in if confirmed as transportation secretary.

LGBTQ rights organizations praised Biden’s selection as a major step in ensuring the incoming administration reflects the country’s diversity.

“Mayor Pete Buttigieg was open and honest about his identity throughout his time on the national scene, giving a voice to our community, and a new vision of who and how our leaders can love,” Human Rights Campaign President Alphonso David said in a statement. “His voice as a champion for the LGBTQ community in the Cabinet room will help President-elect Biden build back our nation better, stronger and more equal than before.”

Buttigieg came out publicly in 2015 through an essay in the South Bend Tribune while seeking reelection as mayor. He was elected with 80% of the vote, more than he received during his previous election.

“This will be a historic milestone for LGBTQ visibility. Pete’s experience and skills as a leader, manager and brilliant communicator, combined with his heartland roots and his unqualified commitment to diversity and equality, will improve the lives of all Americans as Transportation Secretary,” GLAAD President and CEO Sarah Kate Ellis responded on Twitter. “Congratulations to Pete and his husband Chasten on their groundbreaking new roles.”

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