Former United States president Barack Obama has taken to Facebook in an annual tradition to reveal his favourite songs of the year.

The list, posted on Monday, includes some surprising pop picks from the likes of ex-One Direction frontman Harry Styles with Sign of the Times and DJ Khaled's chart-topping track Wild Thoughts with Rihanna.

"It was a nice way to reflect on the works that resonated with me and lift up authors and artists from around the world," Obama said in his post.

Apart from its Top 40 mainstays, the playlist also covers a diverse range of genres.

An unreleased blues version of Bruce Springsteen's classic Born in the U.S.A. cops a mention alongside more alternative offerings from The National and Portugal The Man, as well as several contemporary hip-hop songs by artists such as Chance the Rapper and Kendrick Lamar.

These two rap musicians have been highlighted previously by Obama when expressing his admiration for the genre. "Kendrick and Chance are doing amazing work - two artists who frequent the White House," he stated on radio show Sway in the Morning during his presidency.

Obama is known for sharing playlists and music recommendations regularly on social media. A similar gym playlist in 2016 featured Australian singer-songwriter Courtney Barnett with her acoustic Elevator Operator. 

This time Australia is represented in the reading list portion of his year-end picks, with Obama including Dying: A Memoir by late Queensland author Cory Taylor among his top books of 2017.