Selena Gomez appeared completely recovered as she performed with her band The Scene at the Santa Monica Center Plaza, California, on Monday, June 13.
"I do feel better," she told the over 500 fans gathered at the outdoor mall who watched her perform "Who Says" and "A Year Without Rain."
"I want to thank you so much for coming. If you guys came on Friday, I'm so sorry that I couldn't be here. ... I love you guys very much."
Selena was originally scheduled to perform at the plaza on Friday, June 10, to kick off a Mall tour to promote her upcoming film Monte Carlo.
A day earlier, she was rushed to ER at a LA area hospital after she complained of severe headache and nausea while appearing on Jay Leno to promote Monte Carlo.
At noon on Monday, a recovered Selena took to her Twitter account for the first time following her hospitalization.
"Feeling much better, thank you all for being so understanding. Can't wait to see you all today at Santa Monica Place for the Monte Carlo kick off." she tweeted.
A source told E! Online, "She spent the weekend resting and feels stronger. No more nausea or dizziness."
Following her initial treatment, Selena returned to hospital on Saturday, June 11 for a follow up medical checkup.
Quizzed about the cause of her illness, Selena said, "I was just very malnourished, so I was low on iron and exhausted."