Demi Lovato has hinted she could be set to go a "bigger tour" than her two gigs lined up for September.

The 19-year-old singer-and-actress explained her two intimate concerts in New York and Los Angeles - which sold out in 30 minutes - later this month are a "thank you" to her fans for buying latest single 'Skyscraper' from her forthcoming 'Unbroken' album - and she admitted they could be a prelude for a longer run of shows.

She told MTV: "It definitely is [a preview]. I wanted to say thank you to my fans. I wanted to show them how thankful I am for the support they gave me for 'Skyscraper'.

"At this point, 'Skyscraper' has done so well because of them, and I want to show them how thankful I am.

"And hopefully when I perform the concerts, 'Unbroken' will be coming out. I'll be really nervous to get back onstage for the first time since then, but I'll be really excited.

"It could be a tease for a bigger tour. I don't know."