When it comes to singing competitions, there are a few people who are synonymous with the brand. On one hand, there is Blake Shelton, who has been a long-running coach on The Voice, and on the other, there's Kelly Clarkson, who won the inaugural season of American Idol. These days, both of these music superstars are featured together as coaches on The Voice, but their relationship goes far beyond that of co-workers.

The relationship between Kelly Clarkson and Blake Shelton stretches over many years, and features ties to the music industry as well as friends and family. These two have a great relationship, and now fans are able to see that on the screen each week. The real question is - just how deep does their relationship go?

13 Known Each Other For Years

Blake has amassed a very impressive music career over the past twenty years, which is actually around the same time Kelly won the first season of American Idol. While their paths crossed professionally, they actually became more well-acquainted through mutual friends like Reba McIntyre. Their relationship is much deeper now, and almost like family, but they knew each other long before The Voice.

12 The Voice's Friendly Rivalry

With such a close relationship comes all the great things that go along with it, including a friendly rivalry between two superstars of the music industry. Shelton is almost like The Voice royalty given his long-standing term as a judge on the show, but that does not stop Kelly from challenging him as often as possible. Regarding their rivalry, Shelton told People Magazine that while Kelly is his friend, to "But when she’s on this show, she is my enemy".

11 Clarkson's Husband Is Blake's Manager

Being such big stars in the music industry has certainly bonded Clarkson and Shelton over the years, but they share an even bigger connection - family. While they are not related directly, they do business together so frequently that it almost makes them family. In fact, Blake's livelihood directly impacts Kelly's family since her husband is his talent manager.

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Brandon Blackstock has been Blake's manager through most of his career, which gives Kelly and Blake even more contact when they are not on The Voice together.

10 Her Kids Love Blake

Kelly is the mother to four children - two of her own and two from her husband's previous marriage - and reportedly they all "love Blake". Clarkson told People Magazine that Blake has a "gravitational pull" about him which draws others in. Blake's charm has always been one of his highly rated qualities, and apparently it even works on children as they love being around him!

9 Makes Appearances On Her Talk Show

Blake Shelton is always willing to help out a friend, even if it means appearing on day time television. Shelton has appeared twice on Kelly's talk show, The Kelly Clarkson Show, as both an interviewee and musical entertainment. Blake is never one to shy away from an opportunity to appear on television, but considering that this was a way to help the success of his friend's show, he jumped at the opportunity.

8 She Respects His Choice Of Talent

While success after winning The Voice is not guaranteed for winners of the show, one thing is for sure - Blake Shelton pushes hard for them to have a great career once they have won. Clarkson is very admirable about this part of Blake's coaching philosophy, and while they may be rivals on the screen, she appreciates now he "pushes for his artists". Blake loves the music business, and uses his influence as a judge to make sure great people succeed, and Clarkson aims for the same.

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7 Their Arguments Have Gone A Bit Too Far

Things may be sunshine and rainbows between the two most of the time, but sometimes their play-fighting can go a bit too far. In an interview for Extra TV, what started out as a playful argument went a little too far and seemed to hurt some feelings. The two singers began bickering about a proposed Christmas song featuring the two that never came to pass, but something Blake said struck a nerve with Kelly and the argument became more heated than anyone expected.

6 Blake Almost Officiated Kelly's Wedding

Closeness between co-workers is one thing, but the relationship that Kelly and her husband have with Blake has almost become more than that. In certain states, Blake is an ordained minister and has officiated weddings for friends in the past, like Trace Atkins. So when his manager and Kelly Clarkson were getting married in 2011, he offered up his services, but things did not pan out.

5 She Changed Her Judge's Seat To Be Away From Him

Having friends by your side at work can be fun, but it can also become very taxing to not get a break from someone you know. Kelly knows this all too well - not only is Blake a close friend and a co-worker, but he was also situated directly beside her for all tapings of The Voice. However, Kelly asked not to be seated next to him during her second season to create some distance between the two. While she still loves Blake, she stated she wanted the move so he "didn't annoy her as much".

4 He Always Teases Her About Talking Too Much

The rivalry between Clarkson and Shelton on The Voice is one of the most enjoyable parts of the show when they are placed opposite each other. In fact, it even surpassed the rivalry between Adam Levine and Blake that was front and center for most of the show, particularly since Levine's departure.

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During their first season competing against each other, Blake said that he would use his clout for winning against Kelly to make her "shut up for just five minutes". Complete fun and games, but poking fun at how much she talks is one of Blake's favourite pastimes.