Sykes, member of The Wanted band, was seen getting cosy with Grande at Disneyland recently, which fuelled rumours about them, but the couple never confirmed the affair.
However, they opened up about it on Twitter on Tuesday.
"So, I guess it's obvious now. Thanks to everyone who is being so lovely. I'm so happy but we are terrified," Sykes tweeted.
Grande responded tweeting: "We hesitated saying anything as people can be a bit insensitive, but thank you. We value all of your happiness, thank you for valuing ours."
--IANS (Posted on 26-09-2013)