Rihanna has previewed two new songs, Digital Spy reports.

The singer teased snippets from two previously unheard tracks - 'American Oxygen' and 'Higher'.

American Oxygen' features in the television commercial for NCAA March Madness.

Meanwhile, Rihanna took to Instagram to share two snippets from the string-heavy 'Higher', with a caption suggesting that she has been in the studio with Kuk Harrell and Marcos Tovar.

"5 am drunk off da whiskey with these two rockstars @officialkukharrell @djanser !!! These guys always hold me down even at the craziest hours! We've made every album since #GoodGirlGoneBad together! The family!!! One Love #R8," the singer wrote.

Rihanna has already premiered 'FourFiveSeconds', a collaboration with Kanye West and Sir Paul McCartney.

The singer has also unveiled 'Towards the Sun', a track for the upcoming animated film Home.