Rihanna resumed her 'Diamonds' world tour last night (14.03.13).

The 'Stay' singer was back on stage in Philadelphia, Pennsylvania, after being forced to cancel two shows due to laryngitis, and appeared in good spirits ahead of the show.

She tweeted: ''One of my favourite cities in America #PHILLYnation #DiamondsWorldTour WE BACK!!!!! (sic).''

Rihanna had to cancel dates in Boston and Baltimore after falling ill immediately after the first show of the tour in New York state and tweeted she was ''embarrassed'' about it.

She wrote: ''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 (sic).

''I hate disappointing people that never ever let me down!! I'm so embarrassed about this! Thank you for your prayers and well wishes!(sic).''

The singer will reschedule both of the missed dates and intends to give fans a special show when they do happen.

A source close to the singer told website Hollywood Life: ''She hopes her fans give her another chance and you know she's going to give the crowd in Boston and Baltimore a little extra.''