My mother had a large influence in my becoming a singer.
That singer got quite a tan, didn't she?
I used to be a singer when I was kid. Well, who am I kidding, I’m still a singer now.
Remember how 手 can sometimes refer to a person? In this case, we have a song person (or perhaps a "person who handles songs"). What is a song person also known as? A singer.
The readings are on'yomi readings. You've learned them both already (you learned 手's on'yomi reading with word 投手), so you should be able to read this like a singer sings with a bunch of cashews かしゅ in their mouth. FAST AND LOUD!