( CNN ) -- Sean Kingston is walking around Miami 's Jackson Memorial Hospital eight days after he was brought there in critical condition following a personal-watercraft crash , the publicist for Epic Records said Monday . Kingston , 21 , has been upgraded to serious condition , publicist Joe Carozza said . `` Sean is breathing on his own and walked for the first time this morning , '' Carozza said . Two sources close to the hip-hop artist told CNN last week that doctors expected Kingston to need about six weeks to recover . He suffered a broken jaw , a fractured wrist and water in his lungs , according to the sources , who both asked not to be identified since they were not authorized to speak to the media . Cassandra Sanchez , 23 , was riding on the Sea Doo personal watercraft with Kingston when it crashed into a Miami bridge on May 29 , according to an accident report from the Florida Fish and Wildlife Conservation Commission . Sanchez was also injured and hospitalized . Kingston had bought the Sea Doo just days before , as he was moving into a new house in Miami , one of the sources said . His life vest apparently fell off during the crash , causing him to sink below the water , according to witnesses . `` They were calling us over , telling us , 'He 's drowning , he 's drowning , ' `` said Carmen Rivera , who was boating nearby with her husband , Jonathan Rivera , and friend Jimmy Vega . The three rescuers were interviewed by CNN affiliate WSVN-TV . `` We jumped in the water to help him keep his head above water , '' Vega said . `` I pushed him up , and he was vomiting what seemed like water , and then there was some blood coming out , '' Jonathan Rivera said . The Miami-born artist changed his name from Kisean Anderson to Kingston to reflect his Jamaican heritage . He shot to fame in 2007 when his debut song `` Beautiful Girls '' became a No . 1 hit in the United States . CNN 's Denise Quan contributed to this report .
Sean Kingston 's condition is upgraded to serious , his doctor says . The singer was out for the first time since the accident . He and a friend were injured in a watercraft crash on May 29 in Florida .