Niall Horan has started work on his first solo album.

Niall Horan

Niall Horan

The One Direction star was spotted leaving London's Tileyard Studios on Sunday (10.07.16) where he is believed to be laying down songs for his first record since the 'History' hitmakers went on an extended hiatus.

A source told The Sun Online: "Niall has been busy working at the studio and he kept to himself when he popped outside for a cigarette break.

"He looked like was in deep thought as he was pacing up and down in front of the building before going back inside to continue work."

The 22-year-old singer would be the second of the group to launch a solo career, after Zayn Malik quit in March 2015.

Meanwhile, Harry Styles is believed to have signed a £80 million record deal with Columbia Records, however, he's currently tied up filming Christopher Nolan World War II drama, 'Dunkirk'.

As for the other members, Liam Payne has put his plans for a solo career on hold to enjoy precious time with his girlfriend Cheryl.

And Louis Tomlinson is busy looking after his son Freddie Reign, who he has with his ex-girlfriend Briana Jungwirth.

It comes after it was revealed Niall had been in negotiations with One Direction;s label Syco about signing a deal for his own music, with his first single expected to be released next year.

A source previously revealed: "Niall is the band's secret weapon - Modest Management and Syco believe he has what it takes to become a solo star.

"He has the songwriting and music talent, good looks and cheeky Irish personality which made him a favourite in the States. A deal with Syco is going to be signed in the coming weeks and Niall is already back in the studio writing.

"There's a hit single there too, which will probably be released early next year."