Rihanna reportedly kept school students waiting for hours after she got stuck in traffic.
The Diamonds star was over four hours late for an appearance at Barrington High School in Chicago, where she was greeting competition winners, reported The Chicago Tribune. She had asked schools to create videos showing off their charitable work.
The 25-year-old singer tweeted updates as she got caught in a traffic jam.
"On my way to Barrington High School in Chicago! I can't wait to meet these kids man! They're major inspirational life changers," she wrote.
She later added: "This Chicago traffic is not working," with a picture of her car sitting in traffic.
As she waited, Rihanna - who continues on her Diamonds world tour - praised the school's hard work on the social networking site.
"They raised 40 thousand dollars for Joplin Missouri after the tragic tornado hit Missouri in May last year. They participated in the relay for life for the American Cancer Society and raised 700,000 dollars," she wrote.
"They partnered up with Gigi's Playhouse a Down syndrome awareness centre and created a video for their banquet and raised 245,000. They travel to S Dakota every year to help the people of the Native American community on the crow creek reservation! They raised 35,000 to build houses and help meet the needs of the communities," she continued.
The Chicago Tribune reported that students, who apparently thought it was "rude" that Rihanna was so late, quickly forgot their anger when the songstress finally arrived.
As she left, Rihanna tweeted: "BHS thank you man! You guys RULE! I love this school!"