If you want to know how a birthday greeting is done right, Katy Perry will show you. Especially if it's for a loved one.

Last Friday night (December 15), the "Swish Swish" singer had her entire concert audience sing "Happy Birthday" on a big phone.

Gathering a crowd of at least 10,000 people, Perry took some time during her Tampa show to call up her mother, Mary Hudson, and greet her a happy 70th birthday with the arena as her backup singers.

However, the singer woke up to unfortunate news the next morning, Mary's real birthday, as her family were asked to evacuate their California home due to the ongoing wildfires in the state.

Katy Perry's family aren't the only ones fleeing their homes. Oprah, Ellen Degeneres, John Legend and Chrissy Teigen are some of the many celebrities who were also asked to evacuate their homes.

Watch the full birthday greeting below.

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