Ariana Grande has been seen leaving Niall Horan’s house in the early hours of the morning.

The 21-year-old singer is currently in London on the UK leg of her The Honeymoon world tour.

And just two days after prompting romance rumours when she and One Direction star Niall partied at a burlesque club in the capital on Monday, Ariana fuelled the relationship allegations once again.

Pictures have emerged of Ariana leaving 21-year-old Niall’s Hertfordshire mansion at around 3am on Wednesday morning, after arriving at 10pm on Tuesday night.

The images show Ariana looking as stunning as ever in a pair of tight leather trousers as she leaves the property accompanied by several members of her entourage.

Ariana has been single since splitting from Big Sean in April after eight months together.

Meanwhile, it was reported earlier this week that Niall is also single once again after ending his romance with Australian beauty Melissa Whitelaw.

"Niall and Melissa did well to keep their romance low-profile during their time together,” a source told Britain’s The Sun newspaper.

"They were really close and had fun whenever they went out together. But realistically they always knew it was going to be tough, keeping a relationship going with such distance between them.”

Niall is currently in the UK on a break from his group’s world tour, On The Road… Again.

The group have been in the headlines recently due to former bandmate Zayn Malik sensationally quitting the five-piece earlier this year.

Zayn is now concentrating on a solo career.