The Ospreys rookie King and Coombs were among the six uncapped players in Rob Howley's Championship squad.
Coombs has started both matches to date and has been hugely impressive on both occasions with a colossal work-rate.
King is still waiting for his first taste of Test rugby but he hopes to follow in the footsteps of the Newport Gwent Dragons lock.
"If you look at how he's played his first two games he's been outstanding," said King.
"He's been one of the best players in the team. His work-rate's phenomenal in the game.
"I think that anyone who doesn't get picked is obviously going to be disappointed. All I can do is just play as well as I can."
Coombs will retain his place in the Wales team against Italy after Howley opted to keep faith with the side that triumphed over Italy.
And King, who has been released back to the Ospreys this weekend, admits the competition within the Wales squad is fierce.
"There's going to be great competition for any place. Everyone wants to play and everyone is going to try and do their best," said King.
"But he's [coach Howley] come out and said: 'If it's a winning team, why would you change something that's not broken?'"
"We've been released to come back and play this week so it gives us good preparation to back to our regions.
"Obviously coming back to the region we've got a job to do because we've got a title to defend."
But King has enjoyed his time with the Wales camp and is eying the summer tour to Japan.
"I've been enjoying the training experience," added King.
"It's been a really good experience being around the boys and see what the environment is like.
"If I'm given the opportunity to go on that tour I'll obviously be delighted.
"But at the moment I'm just trying to keep my head down, train as hard as I can and whoever I'm picked to play for I do my best job for them."