The Kansas City Chiefs' overtime defeat of the San Francisco 49ers in the Super Bowl, with Taylor Swift cheering in the stands, drew a record 123.7 million U.S. viewers, according to Nielsen estimates on Tuesday.

It was not only the largest viewership recorded in the 58-year-history of the Super Bowl, but also, according to Nielsen data, the biggest U.S. audience for any event since the first astronauts walked on the moon in 1969.

The NFL's championship game averaged 120.3 million viewers on CBS alone on Sunday, topping last year's audience for the Super Bowl, which drew a record 115.1 million viewers, according to Nielsen.

Additional viewers watched the game on kid-friendly Nickelodeon channels, the Spanish-language broadcast on Univision, and on streaming services such as Paramount+ and NFL+. The audience figure also includes those who watched in places such as bars and restaurants.

CBS reported a slightly smaller audience of 123.4 million on Monday, relying on preliminary data.

By comparison, an estimated 125 million to 140 million people watched U.S. astronauts take the first steps on the moon on July, 20, 1969. The event was shown on three broadcast networks, the only television channels at the time.

Sunday's game featured a halftime performance by R&B superstar Usher, who was joined by Alicia Keys, H.E.R.,, Lil Jon and Ludacris.

Swift, who is dating Chiefs tight end Travis Kelce, was shown celebrating, chugging a drink and biting her nails during tense moments from a suite at Allegiant Stadium in Las Vegas.

"There were several factors driving unprecedented buzz for the big game, from the record-breaking ad spend to the Taylor Swift effect," said Ashwin Navin, co-founder and CEO of Samba TV, a data and measurement firm that estimated the game was watched in 39 million homes.