Christina Aguilera is happy to report that her eldest son Max is "so endearing and sweet" to her 5-month-old daughter Summer Rain.

"He's the big helper and the big teacher so he's awesome. He's just so loving and sweet," the singer and "The Voice" coach told "Extra" of her 7-year-old son from her marriage to Jordan Bratman.

"I'm like, 'How old are you?' He's like a grandma to her, he's just like, 'I'll teach you everything.'"

Aguilera welcomed baby Summer Rain, her second child and first with fiance Matt Rutler, in August. In one of her first interviews since giving birth, the singer said she felt "blessed" with the new addition to her family and discussed the rapport between her two children.

"He's in school," the singer said of Max, who is always instructed to wash his hands before touching the baby. "There's a little age gap, but it's perfect though because then they don't fight over toys," she added.

As for her return to the studio, where she'll be working with fellow "The Voice" coach Pharrell, Aguilera says she is "very excited to pour my heart out into this record fully."

"I've been gathering and writing and coming up with these amazing ideas for different parts of how I was feeling the past year, so I'm really excited to vocalize all of it and make it all come together," she said.

In addition to working on her eighth album, Aguilera will return to "The Voice" as coach for the reality competition's next season.