About 270 miles from Gwyneth Paltrow's L.A. abode, Jennifer Lawrence made it clear Chris Martin belongs to her now. At the Wet n Wild-sponsored iHeartRadio festival in Las Vegas September 19, the actress, 24, was spotted in the VIP section putting her hand over her heart when her rocker boyfriend, 37, took the stage with Coldplay. And her displays of devotion didn't end there. The witness further notes, "When the group played 'Sky Full of Stars,' she screamed ¬really loud - and sang all the words!"