Pop megastar Billie Eilish will play an intimate gig at Camden's Electric Ballroom tonight.

The 21-year-old, who became the youngest to headline Leeds and Reading Festival at the weekend, will swap performing in front of thousands for a 1,500-capacity crowd at the Camden High Street venue.

Announcing the now sold-out concert on her Instagram stories she wrote: "London doing a special lil performance for you. If you signed up for email alerts at my pop-up this week, you’ll get an email with a unique code to access tickets."

This Is Local London: Camden Town's Electric Ballroom has previously hosted gigs by the likes of Prince, U2 and Paul McCartney.Camden Town's Electric Ballroom has previously hosted gigs by the likes of Prince, U2 and Paul McCartney. (Image: Archant)

Her gig comes the day before a sold out concert by brother, co-writer, and producer Finneas, whom she calls her "best friend in the world."

Finneas accompanied his sister during her huge festival appearances which saw the Brit, Grammy and Oscar winner perform the likes of Ocean Eyes, OxytocinBad GuyHappier Than Ever and her ballad What Was I Made For? from the Barbie soundtrack.

This Is Local London: Billie Eilish headlined at Reading Festival this weekend.Billie Eilish headlined at Reading Festival this weekend. (Image: Ben Awin)

He has won eight Grammy awards for his work with Eilish, shares an Oscar for co-writing the Bond theme No Time To Die and has released several singles and an album as a solo artist.

On Wednesday August 30th he plays his own sold out concert at Electric Ballroom, a former Irish dance hall, roller disco and indoor market venue which has hosted gigs from the likes of Prince, U2, The Killers, and Paul McCartney.