"Now and Then" is a song by the English rock band the Beatles, released on 2 November 2023. Dubbed "the last Beatles song", it appeared on a double A-side single, paired with a new stereo remix of the band's first single, "Love Me Do" (1962), with the two serving as "bookends" to the band's history. Both songs were included on the expanded re-issues of the 1973 compilations 1962–1966 and 1967–1970, released on 10 November 2023.

"Now and Then" originated as a ballad that John Lennon wrote and recorded around 1977 as a solo home demo but left unfinished. After Lennon's death in 1980, the song was considered as a potential third Beatles reunion single for their 1995–1996 retrospective project The Beatles Anthology, following "Free as a Bird" and "Real Love", both based on two other Lennon demos of the same names. Instead, due to production difficulties, it was shelved for nearly three decades, until it was completed by his surviving bandmates Paul McCartney and Ringo Starr, using overdubs and guitar tracks by George Harrison (who died in 2001) from the abandoned 1995 sessions.

The final version features additional lyrics by McCartney. Lennon's voice was extracted from the demo using the machine-learning-assisted audio restoration technology commissioned by Peter Jackson for his 2021 documentary The Beatles: Get Back. Jackson also directed the music video for "Now and Then". The song received widespread acclaim from critics, who felt it was a worthy finale for the Beatles. It topped the charts in the United Kingdom, Germany, and Austria, and reached the top ten in Australia, Belgium, Canada, Ireland, Japan, the Netherlands, Sweden, Switzerland, and the United States. It is the only Beatles UK number-one single not attributed to the Lennon–McCartney songwriting partnership. The song was first performed live by McCartney on 1 October 2024 as part of his Got Back tour at the Estadio Centenario of Montevideo.