Sir Paul McCartney is inviting fans to a top secret shingdig in London next week.

Sir Paul McCartney

Sir Paul McCartney

The Beatles legend has asked his 3.8 million followers to record a short video on Twitter explaining why they are worthy of a place at the special event he's hosting in the British capital, along with the mysterious hashtag #UnderTheStaircase.

The competition comes ahead of the release of the 76-year-old rocker's 17th studio album, 'Egypt Station', which drops on September 7.

He tweeted: "Why do you think you should attend a secret event in London with Paul next week? Post a short video using the hashtag #UnderTheStaircase [sic]"

The 'Let it Be' hitmaker - who so far has released the tracks 'I Don't Know' and 'Come On To Me' from his 17th solo record - has been known for hosting secret gigs to launch new music and surprising fans with impromptu pub sets since the start of his career.

In 1971, the Liverpudlian and his late ex-wife Linda, who were in the band Wings at the time, travelled across the UK in a small van and turned up at small venues and clubs to perform.

Meanwhile, McCartney could be set to headline Glastonbury Festival when it returns next year.

Boss Emily Eavis - daughter of founder Michael - has admitted the iconic star is always a name she would welcome to the world famous Pyramid Stage.

She said: "We always want him, of course, He's top of our list - but we'll have to see."

Her coy comments came after the 'Hey Jude' hitmaker admitted to BBC Radio 2 host Jo Whiley he would be delighted to top the bill at the festival for the first time since 2004.

He said last month: "I haven't really spoken to anyone about it. It's a little while since we did it. And we did enjoy doing it. The conversation hasn't gone any further."

Jo then asked: "If you were asked though what would you say?"

And Macca - who will return to the UK for the first time in three years in December with gigs in London, Glasgow and Liverpool - replied: "Yeah probably, probably."