As they celebrate their 20th year as a band, American indie rock luminaries The National mark the milestone with I Am Easy To Find.

It is a work that brings the band's experimental tendencies to the fore. With 16 songs clocking slightly more than an hour, chopped-up guitar lines and imaginative drumbeats sit next to lush strings and choral arrangements, ramping up the moody vibes and dramatic tension found throughout the release.

The cinematic quality could be intentional - the album is a collaboration with American film-maker Mike Mills, an Oscar-nominee known for indie films such as 2016 comedy-drama 20th Century Women.

Mills had directed a short film starring Oscar winner Alicia Vikander that shares the title of the album and uses some lyrics and music from it. However, he and the band insist that the two are separate projects.

What stands out the most is how much baritone-voiced frontman Matt Berninger gives way to other voices who either sing with him or take the lead. These are all acclaimed women singer-songwriters.

American musician and singer Gail Ann Dorsey, best known as a prominent member of David Bowie's band, takes the lead halfway through album opener You Had Your Soul With You and pairs her voice with Berninger's again on other tracks such as the intricately textured Roman Holiday and the poignant Hey Rosey.

Together with French singer Mina Tindle, wife of band guitarist and songwriter Bryce Dessner, Berninger muses on matrimony on the piano-led Oblivions.

British singer-songwriter Kate Stables features on songs such as the title track and the upbeat Rylan, a live favourite from the band who is finally given its own studio recording, while Eve Owen balances the frantic pace of Where Is Her Head with her reassuring voice.

Other songs feature acclaimed women artists such as American singer-songwriter Sharon Van Etten (The Pull Of You) and Irish singer-songwriter Lisa Hannigan (So Far So Fast).

When he takes back the microphone, Berninger grapples with heartbreak on the beautifully melancholic Quiet Light ("I'm not that spiritual, I still go out all the time to department stores/Everything I need, but none of this is getting me anywhere good").

One of the longest songs in the album, Not In Kansas, features him in a contemplative mood, referencing seemingly disparate ideas - from religion to indie bands R.E.M. and The Strokes, often in the same verse.

There are many haunting moments in the album, including the pianos in Hairpin Turns and album closer Light Years.

When the Brooklyn Youth Chorus choir takes over all of the singing in Dust Swirls In Strange Light, their chants become a unique foil to the band's unconventional instrumentation.