United Kingdom, May 10 -- Blake Shelton is delighted to see his stepsons showcasing their musical talents.

The 48-year-old country singer has watched Kingston, 18, and Zuma, 16, - whose parents are his wife Gwen Stefani and her former husband Gavin Rossdale - perform at his bar and restaurant Ole Red in Oklahoma and is happy to see them pursuing their passion for the art form.

In an interview with People, Blake said: "When they get up there, you would assume they've been doing for 10 years. They're very comfortable and not rattled at all.

"They have three professional musicians in their life and have grown up standing on the side of the stages watching this in their entire life, so they have it on their mind how to be when they get out...