Philadelphia, PA -- Demi Lovato is a no-go for Philadelphia's Fourth of July show.
City officials say Lovato has canceled her appearance at Thursday's annual free concert because of strep throat. She's being replaced on the bill by 22-year-old country singer Hunter Hayes.
Desiree Peterkin-Bell, a city spokeswoman, says officials are sad that Lovato can't play but are glad to have Hayes, adding he's that he's "one of the biggest stars in country music right now."
Lovato tweeted Wednesday that "I can't sleep cause my throat hurts!!!"
The city's annual Independence Day concert will also feature John Mayer, Ne-Yo and J. Cole along with hometown hosts The Roots. Other performers will include Philadelphia-born singer Jill Scott, as well as Grace Potter and Ben Taylor.