Rihanna has expressed her relief and joy at resuming her tour following illness.

As previously reported, the superstar singer recently cancelled two dates in America due to laryngitis - one in Boston and one in Baltimore.

The 'Stay' star was regretful after the news broke of the first cancellation, tweeting:

"#BOSTON this is the hardest thing for me to deal with! I feel like we've been waiting on this day forever, and I'm hurt that I let you down. I hate disappointing people that never ever let me down!"

However, she resumed her 'Diamonds' world tour last night (March 14) in Philadelphia, with the superstar singer expressing her joy through Twitter:

"One of my favorite cities in America #PHILLYnation #DiamondsWorldTour WE BACK!!!!"