(Reuters) - Tech billionaires, foreign diplomats and CEOs shadowed U.S. President Donald Trump on Monday, with several attending St. John's Church in Washington and seated prominently on the dais in the U.S. Capitol ahead of his speech. 

The church service, typically a little-noticed part of Inauguration Day, quickly became a "who's who" parade of some of the United States' - and the world's - wealthiest individuals, as attendees entered the downtown church near the White House. Tech executives' embrace of Trump, including billionaires such as Elon Musk in Trump's inner circle, has become a major theme of Trump's transition into power, and sparked warnings from former President Joe Biden. 

Below is a non-exhaustive list of some Inauguration Day attendees.

TESLA CEO ELON MUSK 

Musk, the world's richest man and head of Tesla, SpaceX and X, spent more than a quarter of a billion dollars to help elect Trump in November, and Trump has tapped Musk to lead a department aimed at creating a more efficient U.S. government.

He arrived at the church service alone. 

TIKTOK CEO SHOU ZI CHEW     

One day before Trump's inauguration, TikTok thanked him for what they said was his role in restoring service of the app to American users. As TikTok faced a Sunday ban in the U.S., Trump said he would revive the app's access in the U.S. when he returned to power on Monday, adding that the U.S. will seek a joint venture to restore the short-video sharing app used by 170 million Americans.

META CEO MARK ZUCKERBERG

Since Trump was elected in November, Zuckerberg announced that his social-media company Meta Platforms ( META ) scrapped its U.S. fact-checking program and reduced curbs on discussions around contentious topics such as immigration and gender identity, bowing to criticism from Trump's conservative supporters. Zuckerberg has tried to mend fences with the new administration, while Trump in the past pledged to imprison the CEO. 

Zuckerberg arrived at the church with his wife, Priscilla Chan, a pediatrician. 

MIRIAM ADELSON 

Casino billionaire and Republican mega-donor Adelson led the Preserve America super PAC, which boosted Trump. Born in Israel, Adelson and her husband Sheldon were crucial backers in Trump's first presidential win. 

INDIAN BILLIONAIRE MUKESH AMBANI     

Ambani, the richest man in India, heads Reliance Industries, India's most valuable company involved in businesses including energy and retail. Ambani also attended Trump's pre-inauguration ceremony.

THE ARNAULT FAMILY 

LVMH CEO Bernard Arnault attended with his wife Helene Mercier and two of his children, Delphine Arnault and Alexandre Arnault. All of Arnault's five children hold prominent positions in his luxury-goods group, the world's largest. Delphine Arnault heads the fashion label Dior, while Alexandre, who has played a key role rebranding its American jewelry label Tiffany & Co., is returning to France from the United States to help run the group's wines & spirits division. The Arnault family is France's wealthiest, with a holding in LVMH worth around $200 billion.

AMAZON ( AMZN ) CEO JEFF BEZOS 

Bezos, who also runs the rocket company Blue Origin and the Washington Post newspaper, defended his paper's decision to not endorse a U.S. presidential candidate ahead of this year's election. The decision blocked an endorsement of Trump's political opponent Kamala Harris. 

Amazon ( AMZN ) will stream Trump's inauguration on its Prime Video service. Bezos's fiancee Lauren Sanchez arrived at the Capitol with him. 

GOOGLE CEO SUNDAR PICHAI     

Alphabet's Google, along with other companies such as Amazon ( AMZN ) and Meta, donated $1 million each to Trump's inaugural fund. Trump will likely dial back some of the antitrust policies pursued under former President Joe Biden, potentially including a bid to break up Google over its dominance in online search, experts said.

FORMER UK PRIME MINISTER BORIS JOHNSON    

Johnson, who was once dubbed "Britain Trump" by Trump himself, met with Trump in 2023 to discuss "the vital importance of Ukrainian victory" over its invasion by Russia. Johnson had been keen to forge a profile as one of Ukraine's most ardent backers in its fight against Russia.