American rapper and singer Post Malone has said he is “beyond honoured” to have collaborated with Taylor Swift on her new album The Tortured Poets Department.

The Congratulations singer, 28, features on Swift’s single Fortnight, which became Spotify’s most-streamed song in a single day after its release.

On social media the musician, whose real name is Austin Richard Post, said: “It’s once in a lifetime that someone like @taylorswift13 comes into this world.

“I am floored by your heart and your mind, and I am beyond honored to have been asked to help you with your journey I love you so much. Thank you Tay.”

On April 18, Swift, 34, announced online that Fortnight was the first single on her record and said a music video would drop after the album.

She also said she had been “a huge fan of Post because of the writer he is, his musical experimentation and those melodies he creates that just stick in your head forever.”

She added: “I got to witness that magic come to life firsthand when we worked together on Fortnight.”

Her music video for the track includes an appearance from Dead Poets Society stars Ethan Hawke and Josh Charles, as well as Post Malone.

The video appears to tell the tale of star-crossed lovers set in a dystopian romance.

It was during the Grammys in February that the Anti-Hero singer, who has been touring the world this year, said that her 11th studio album would drop on April 19.

The record, which includes a collaboration with Florence And The Machine, achieved more than 300 million streams in a single day after its release, according to music streaming platform Spotify.

Hours after dropping the 16-song edition of her album the US pop superstar announced an expanded version with an extra 15 songs, titled The Anthology.

The Bad Blood singer, who is known for taking inspiration from past relationships for her music, has placed So Long, London at number five in the album’s tracklist – the slot reserved for the most meaningful song on each of Swift’s records.

The song is thought to offer new insight into her split from The Favourite actor Joe Alwyn after six years together.

Before the album’s release, fans had speculated whether the album title was a reference to Alwyn.

In December 2022, Alwyn and Normal People star Paul Mescal said they had a WhatsApp group chat with Fleabag actor Andrew Scott called The Tortured Man Club.

Fans have also speculated that a number of her tracks refer to her blossoming romance with NFL star Travis Kelce.

In addition to his collaboration with Swift, Malone recently featured on Beyonce’s highly anticipated Act II: Cowboy Carter on the track Levii’s Jeans.