Plan B's businesses earned £4 million in one year.

The 'She Said' singer's companies - Plan B Enterprises and Plan B Touring - took the huge sum in net profit between July 2011 and July 2012, according to his accounts.

On top of that, the busy star - who released his debut as a film director, 'iLL Manors', last year - also made an estimated £2.5 million from record sales.

A source told The Sun newspaper: "Ben has been working night and day for the past few years and it's now paying off financially.

"The earnings from his 'The Defamation of Strickland Banks' album have taken a while to materialise, but now they're coming in by the bucketload."

Despite making money, the rapper hasn't had the time to spend it as he has been too busy on his next projects.

The source added: "Until recently, he never stopped working for long enough to spend his money. All of it was ploughed into more ventures, which will make more money."

Plan B made his first million in 2011 but has remained modest, and not flashed his cash on sports cars or bling.

A source said at the time: "Ben is very clever with his money. He isn't flash like some rappers, who like to immediately spend their earnings on diamonds.

"To be honest, he doesn't even have time to spend the amount he's making, he's too busy working on his next project."

Despite his comfortable financial situation, Plan B said last year he hasn't bought his own house.

He explained: "When I first started renting, this estate agent was walking me around these flats in Hackney [East London] going, 'This is a really great two-bedroom place in a brilliant location'. I was like, 'Are you being serious? This is an ex-council flat, the people next door aren't even paying rent.

"And you're telling me I'd have to pay so much? If I can't afford to buy my own place, I can't even think about how difficult it must be for other people."