John and Paul’s show of solidarity was a measure of the outrage felt about Jagger and Richards’ imprisonment.

The albeit fleeting incarceration of Mick Jagger and Keith Richards after their drug convictions of 1967 was one of the biggest stories of what became known — ironically, in their case — as the Summer of Love.
This extraordinary entry in the history of the Rolling Stones was soon illustrated by the band’s own memorable single inspired by the affair, ‘We Love You.’ At a nighttime recording session at Olympic Studios on 19 July that year, backing vocals and percussion for the upcoming Decca release were laid down by Paul McCartney and John Lennon.
The gesture by the two Beatles was a show of solidarity for their friends and a measure of the outrage felt about Jagger and Richards’ imprisonment. Even as the case was ongoing, an earlier such gesture had been made by The Who, when they recorded swiftly-convened covers of ‘The Last Time’ and ‘Under My Thumb.’

The Stones were at Olympic recording what became Their Satanic Majesties Request, their sixth British album, which followed in December. ‘We Love You’ wasn’t on it, which gives it an even more distinct place in the events of that year. Opening to the sound of prison doors banging shut, it then featured an imposing piano riff by Nicky Hopkins, and defiant Jagger-Richards lyrics that both showed appreciation for their fans’ support during the ordeal, and disdain for the establishment that, in their eyes, condoned it. To make the point even more powerfully, there was a striking promotional film directed by Peter Whitehead.
‘We Love You’ was released on 18 August in the UK and two weeks later in America. It spent most of September in the British top ten, with a No. 8 peak. In the US, ‘Dandelion’ was promoted as the A-side of the single and reached No. 14, but interest and airplay for ‘We Love You’ was enough to earn it a No. 50 peak of its own.

source:udiscovermusic