Several concerts on the tour were cancelled after drummer Patrick Carney broke and dislocated his shoulder in a swimming accident while vacationing in Saint Barthélemy in January 2015.

[9] After concluding the tour with a performance at Outside Lands Music and Arts Festival in San Francisco in August 2015, the group began an extended hiatus.

[10] In 2017, Carney served as a co-writer, producer, and drummer on Michelle Branch's record Hopeless Romantic, her first studio album in 14 years.

Auerbach found the experience inspirational, as it reminded him of his youth when he would attend Schwartz's live performances in Cleveland and then try to emulate his style of guitar playing when jamming with his bandmate Carney.

"[11] The Black Keys re-convened at Easy Eye Sound on September 5, 2018, at 10 a.m. to begin working on "Let's Rock", ending a three-year hiatus.

[15] Besides contributions from two backing vocalists (Leisa Hans and Ashley Wilcoxson), Auerbach and Carney did not collaborate with anyone else to compose the music, and the two co-produced the album.

Auerbach came across the story in a copy of a local newspaper, The Tennessean, that had been left in the studio during the initial recording sessions.

[17] Several months later, when the time came for the group to choose an album title and cover image, he was reminded of the story: "those words kept coming back to me, how absurd they were and how right on the money they were.

[19] The next day, the song was announced as the theme music for television coverage of the 2019 NCAA Division I men's basketball tournament.

"[11] The band filmed a facetious video for Funny or Die that was released in July, in which they self-seriously offer to teach a MasterClass on writing music.

[26] David Fricke of Rolling Stone said that the band "bring a heightened purism... emphasizing the power-duo force of their early records amid the riffing storm in 'Eagle Birds' and 'Go.'

[1] Will Hodgkinson of The Times said, "There is nothing groundbreaking here, and no great revelation of character, but Auerbach and Carney capture the essence of solid, back-to-basics rock'n'roll in a way that cannot help but make you feel good."

He said listeners not concerned with the album's unoriginality would find it to be a great summer record because "the Black Keys do this kind of thing with such élan".

[34] Eric R. Danton of Paste said that rather than revisiting the sound of their earliest days, the record was a sampler of other styles and strengths of the band members.

If you want something you can crank up at backyard barbecues or in the car with the windows down, well, The Black Keys have two words for you, and they're in the album title.

"[32] Michael Hann of The Guardian said, "The lyrics are rarely more than functional... but the music is persuasive: hard, shining rock, with an irresistible pop edge.

"[3] Patrick Smith of The Independent said that neither of the group's most well-known albums, Brothers and El Camino, "can claim to be as fiendishly catchy as Let's Rock, a record that can scarcely sit still".

"[30] Evan Rytlewski of Pitchfork commented that the absence of Danger Mouse's studio flourishes "leaves more room for riffs, and 'Let's Rock' doesn't skimp on them."

She said that "while there are a few redeeming moments, their reunion doesn't sound remotely close to the work of two musicians reclaiming their best years".

Ultimately, he said the record was "a layered, well-orchestrated affair, and as long as you're willing to let go of any hope of a return to those lean and mean Thickfreakness days, 'Let's Rock' won't disappoint".

The album also made top-ten debuts in Australia, Austria, Belgium, Canada, France, Germany, Ireland, the Netherlands, New Zealand, Norway, and Switzerland.