Getting friendly with John Legend

John Legend's first two albums sold more than five million copies worldwide

As well as being one of the biggest stars in soul and R&B, US singer John Legend is one of the best-connected people in pop.

Signed by Kanye West, he has worked with Jay-Z, Stevie Wonder and Alicia Keys, written for Michael Jackson, played for Barack Obama and produced Estelle's last album.

OutKast's Andre 3000 appears on his new single Green Light, while Kanye, Estelle and Brandy guest on his third album Evolver.

Here, the five-time Grammy winner discusses his life and work through his friends, collaborators and heroes.

KANYE WEST

I met Kanye in 2001 through his cousin. At the time, we were both pretty much unknown to the world.

Kanye had just produced a couple of songs that would be on The Blueprint for Jay-Z, and from that point he progressed to getting a record deal. And he brought me along.

I worked with him on all the projects he was doing and he signed me to his production company Getting Out Our Dreams.

Through working together, I learned a lot from him. He's featured either as a producer and/or a rapper on all three of my albums and obviously I've done a lot of work on his albums as well.

ESTELLE

Estelle's album Shine includes the hit single American Boy, with Kanye West

Estelle's Shine was the first album I signed to my label Homeschool Records.

She revived her career but I gave her an assist. She deserved to be heard by the world. I'm excited to see her being the star that she deserves to be.

Musically, we were very compatible. She's a star, she's a great performer, a great writer, she's got a really special voice and special talent and I just thought people should hear it.

MICHAEL JACKSON

I've only had a couple of run-ins with Michael.

I met him in Bahrain at this Formula One event. He was there with the Crown Prince of Bahrain - Michael was living there for a while.

I wrote a song with will.i.am that we submitted to him that he may or may not use for his new album, and I have no idea what the status of that album is - if it's still actually in the works or temporarily on hold or anything. I have no idea.

I've had no communication from him. I don't even know if he's still working on an album. I have a suspicion that it's not happening.

ANDRE 3000

Andre 3000 (left) puts in a star turn on John Legend's latest single

OutKast have always been one of my favourite groups and I always thought I should work with him.

But I'd only met him once or twice before we did Green Light and I didn't know him that well.

When we finished the beat, it started to sound like something Andre should be on, so we called him, played him the song and he loved it and wanted to be on it.

He's charming and charismatic and all that stuff. But when people are performing, they're a heightened representation of themselves, and in real life they're a little more mellowed out.

STEVIE WONDER

He's a hero of mine and an inspiration for me. I've been influenced by him just about more than any other artist.

We performed together at the BET Awards in 2005 and it was a signature moment during the marketing of my first album, where we performed Ordinary People and My Cherie Amour back-to-back in front of the whole world. That was pretty cool.

BARACK OBAMA

Legend has performed for Barack Obama's US presidential campaign

I've campaigned for Barack and I really believe he's the right man for us to elect as our next president, so I'm doing all I can.

There's no way I could vote for John McCain.

I don't agree with his stance on war and foreign policy, I don't think he has the right ideas for the economy, I don't think his demeanour is right to be the leader of America and by extension one of the most important individuals in the world. I don't think his temperament is one that would represent the country well.

JEFFREY SACHS, economics professor

Jeffrey is a friend and mentor for me. He's an inspiration to me.

I read his book The End of Poverty and was really inspired to get involved in the work that he's doing. We believe that it's possible to eradicate poverty in our lifetimes, and we actually have to do work to make that happen, so that's what we're doing.

We've spoken at colleges together, done a few events together, helped raise money for the cause. I've funded, through my Show Me Campaign, one of the villages in Tanzania which is under his Millennium Villages umbrella.

I learned a lot from him and it changed my life.

VAUGHAN ANTHONY

That's my younger brother - he'll be the next artist we release on Homeschool Records.

I'm really excited about it - we've got some really good new songs we've worked on together.

It's contemporary R&B - his voice isn't altogether different from mine and I think people will clearly hear the family resemblance. But he's got his own swagger, his own vibe.

STEPHEN COLBERT, comedian

He's one of the best comedians around right now - he's a comedic genius, I think he's one of the best.

I've gotten the opportunity to do some musical performances with him on his show a couple of times. I'm in his Christmas special - it's a bunch of spoof songs for Christmas and we did one that's a bit crass. It will be another side of me people haven't really seen.

John Legend was talking to BBC News music reporter Ian Youngs.