Four years ago, a surprise performance by Beyonce at President Barack Obama’s Neighborhood Ball became arguably the most talked-about musical moment of the inauguration festivities.

At the Jan. 20, 2009 event — broadcast on ABC and watched by 12.6 million U.S. TV viewers according to Nielsen — she serenaded the newly-elected president and first lady Michelle Obama with a cover of Etta James’ “At Last.”

Video clips of the performance went viral on YouTube, other TV networks played it repeatedly, and sales of the song immediately surged. Beyonce’s already-released cover version earned a 1,318% sales gain according to Nielsen SoundScan in the tracking week ending Jan. 25. The tune sold 31,000 downloads that week — up from just 2,000 the week previous. (Her version of “At Last” had been released late in 2008 on the “Cadillac Records” soundtrack. She co-starred in the film as James.)

Beyonce is back again for Obama’s second inauguration, though this time she’ll be performing at the Ceremonial Swearing-In Ceremony on Jan. 21. Also on hand for the ceremony: Kelly Clarkson and James Taylor.

Obama’s first inauguration was a major TV event. The Jan. 20, 2009 ceremony was watched by 37.8 million U.S. TV viewers — the second-most-watched presidential inauguration after President Reagan’s first in 1981 (41.8 million). Leading up to that were an array of concerts and balls, broadcast on HBO and Disney Channel, all of which earned many millions of viewers and boasted A-list talent.