The 22-year-old singer, who appeared on the U.S. television talent show in 2014, was killed last week (10Jun16) when 27-year-old gunman Kevin James Loibl opened fire during a fan meet-and-greet following a concert in Orlando, Florida.

Following Christina's death, her mentor on the show, Adam Levine, paid his respects to the singer, writing, "Christina was a natural, a gifted talent that comes along so rarely. She was taken from us too soon."

Gwen, who is also a judge on the show but was not on the panel when Christina competed, has now added her thoughts on the tragedy, saying, "Everybody, you know, is shaken. It's just a shock and... it makes me feel totally vulnerable. Everybody is just horrified."

Christina will be laid to rest on Friday (17Jun16) at the Fellowship Alliance Chapel in Medford, New Jersey. Adam has offered to pay for the funeral.