Inauguration Day may be all about pomp, circumstance, and politicians, but it's also great for celebrity sightings. Before we get to the inaugural balls, where Lady Gaga is expected to perform, here are all the famous people in attendance at the ceremony on the Mall. We'll update with more photos — and GIFs! — as they come in.

Katy Perry and John Mayer
Perry performed at the Kid's Inaugural Concert. Mayer dates Perry. 

They perhaps mocked Aretha Franklin's notorious 2009 inaugural hat: 

Beyoncé and Jay-Z

Beyoncé is performing the national anthem at today's festivities. She posted a shot of herself rehearsing to her Instagram:

Their mothers will also be attending: 

IN-LAWS: Reserved side-by-side seats for mothers of Jay-Z and Beyonce. #inauguration #behindthescenes instagr.am/p/Ut_pXYDBcy/

— Kasie Hunt (@kasie) January 20, 2013

Nick Cannon
Cannon was also at the kid's concert. Here he is chatting with Soledad O'Brien this morning: 

James Taylor 
Taylor is singing "America the Beautiful" at the inauguration.

Kelly Clarkson
Clarkson is singing "My Country Tis of Thee." 

Eva Longoria
Longoria is an inaugural committee co-chair. 

Cyndi Lauper 
CNN has reported spotting the 80s icon/"Girls Just Wanna Have Fun" singer. Lauper has helped the Democratic Congressional Committee fundraising efforts and is performing at the Human Rights Campaign's inaugural celebration.

John Legend and Chrissy Teigen
Legend was honored at the Hip-Hop Inaugural Ball. In this picture he and his fiancée Chrissy Teigen interact with Bill and Hillary Clinton:

Bill Russell
The NBA Hall of Famer was mistaken for Morgan Freeman by ABC anchor George Stephanopoulos. 

Alicia Keys
The singer who is performing at three balls, shared her Inauguration Day photos with People magazine. 

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Esther Zuckerman