(NBC) – “The Voice” enters the Knockout Round phase tonight and that means they bring in a Mega Mentor for all the artists.

Anticipation is half the fun for the contestants, but finding out who will be the Mega Mentor is even better. The singers who are still getting used to working with superstar coaches, now have a megastar mentor, Ed Sheeran.

The quest to win “The Voice” continues tonight with Sheeran providing some knockout guidance.

“Sometimes the runs that you do take away from the emotion of it, so I’d say don’t try and overcomplicate it,” he suggested to one of the singers. “With a song like this, simple is so effective.”

He also provides some inspiration, telling the contestant, “Every single record label told me no at least three times. The one I’m signed to told me no twice.”

And some of Sheeran’s support is not just for the artists.

“I’ve known Ariana, for like, a long, long time. We’ve worked together on songs in the past. We’ve jammed. It’s going to be a good first season for her,” he said about working on the show alongside the newest coach, Ariana Grande.

The artists are hoping it’s an even better season for them.

“The Voice” airs tonight at 8 p.m., followed by a new episode of “Ordinary Joe.”

Multi-platinum global recording artist, Grammy Award winner and talented actress Ariana Grande claims her red chair alongside superstar coaches Kelly Clarkson, John Legend and Blake Shelton as they return for Season 21. Carson Daly returns as host.

The show’s innovative format features four stages of competition: Blind Auditions, Battle Rounds, Knockouts and Live Performance Shows.

During the Blind Auditions, the decisions from the coaches are based solely on voice and not looks. The coaches hear the artists perform but they don’t get to see them, thanks to rotating chairs. If a coach is impressed by the artist’s voice, they push a button to select the artist for their team. At this point, the coach’s chair will swivel so that they can face the artist they selected. If more than one coach pushes the button, the power then shifts to the artists to choose which coach they want to work with. If no one pushes their button, the artist is eliminated from the competition.

Also returning this season is the block, which adds another layer of coach competition during the Blind Auditions. The coach chairs each have an extra set of buttons with the other three coaches’ names on them, which prevents a coach from adding a new artist to his or her team. The coaches can only use their block buttons on one artist for the entire first round of the competition. The blocked coach only discovers they are blocked if they press their button, and though their chair will still turn, their lane lights up with “BLOCKED.” If the coach doesn’t press their button, the block is still available for another audition.

Once the teams are set, the battle is on. The coaches dedicate themselves to developing their team of artists, giving them advice and sharing the secrets of their success, along with help from their celebrity advisors. The coaches enlist music industry heavyweights to prepare their artists for the Battle Rounds. This season’s Battle Advisors include Jason Aldean (Team Kelly), Kristin Chenoweth (Team Ariana), Camila Cabello (Team Legend), and Dierks Bentley (Team Blake).

During the Battle Rounds, the coaches will pit two of their own team members against each other to sing the same song together in front of a live, fully vaccinated in-studio audience, at limited capacity. The artists are vying for their coach’s confidence and decision to take them to the next round.

After each vocal battle, the coach must choose which of his or her artists will advance to the next round of competition. Each coach will have one save and one steal in the Battle Rounds. The losing artist is available to be saved by their own coach, but with the steals still in play, the artist could potentially choose to go with a different coach, leading to even tougher decisions for the coaches and artists. Artists who won their battle, were saved by their own coach or were stolen by another coach will advance to the Knockouts.

For the artists who made it to the Knockouts, one superstar Mega Mentor will be on hand to work with all the coaches and their teams as they prepare the artists for this challenge. In the Knockouts, the artists will be paired against a teammate once more, but this time, they will select their own songs to perform individually while their direct competitor watches and waits. The coaches will choose the winner, and the artist not selected will be available to be stolen by another coach. The stakes are high as each coach will only have one steal in the Knockouts.

Once the Live Performance Shows begin, the top artists will compete against each other weekly during a live broadcast. This time the television audience will vote to save their favorite artists. The artists with the lowest number of votes will be eligible for the Instant Save and will each perform a new song to prove why they should continue in the competition. America will then have the opportunity to save their favorite performer by voting on “The Voice” Official App or NBC.com. Those with the lowest number of votes will be sent home. In the end, one artist will be named “The Voice” and will receive the grand prize of a recording contract.