Grime star Giggs and Lily Allen. Picture: Lily Allen/Instagram

Lily Allen has released her first new song in three years -'Trigger Bang' featuring grime star Giggs.

The 'Smile' hitmaker hasn't put out any tunes since her album 'Sheezus', but surprised fans on Monday night, by dropping the coming-of-age banger about her wild past.

On the track, she sings: "When I was young I was blameless/ Playing with rude boys and trainers/

I had a foot in the rave 'cause I was attracted to danger/

I never got home for Neighbours, hey/ When I grew up, nothing changed much/ Anything went, I was famous

/I would wake up next to strangers/ Everyone knows what cocaine does/ Numbing the pain when the shame comes, hey (sic)"

In October last year, Lily debuted a new track at Mark Ronson's show at The Savoy hotel in London.

The 'Alfie' hitmaker took to the stage to perform three songs at the MasterCard Priceless event, including a brand new electronic dance track which she created with the superstar DJ.

The 32-year-old singer was still learning the words to the as-yet-untitled track as she had to read most of it from a lyrics sheet.

Speaking at the show, which was her first concert in over a year, Lily told the crowd: "I haven't played anything for about a year I'm really nervous."

An album should be on the way from the British star as she told the audience then she'd been in the studio with Ronson, 42.

Before performing the track, she said: "Mark and I have been in the studio a little bit this week."

It was previously revealed Lily has teamed up with the 'Uptown Funk' hitmaker - her long-time collaborator - for her upcoming record and the producer said she'd channeled the heartbreak caused by her separation from Sam Cooper into her lyrics. 

Speaking last year, he said: "We've been writing together again on the new record. I feel like they are some of the best songs she's written. 

"Her voice sounds incredible. The stuff I'm working on is some of her most honest and heartbreaking music ever. She writes so honestly you can feel it."

Mark said he believes the music world needs an "honest" star like Lily - who has two daughters, Ethel, six, and Marnie, four, with Sam - back.

He said: "She's like a needed performer. There's nobody really doing s**t like that, really honest."