Lea Michele is sticking around Fox. But her character on Scream Queens, as teased here, will be VERY different than her character on Glee.
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The single "Cannonball" will be included on Lea Michele's debut solo album. Listen to a snippet here.
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Glee Quotes

I'm gonna miss all of you. I love you guys.

Puck

Relationships are a lot like flowers. If you find the right seed, put it in good soil, give it water and sunlight, bam. Perfect bud. And then comes winter and the flower dies. But if you tend that garden, spring will come along and that flower will bloom again.

Finn