Danny posted a picture with Ryan on Twitter.
Alongside the picture he wrote: "What a pleasure the last five years has been. An incredible actor and a beautiful man.
What a pleasure the last five years has been.
"To share the laughs, the screen and an iconic soap partnership with you has been nothing other than an honour brother!
"Aaron lost his husband. I lose a good friend.
"Farewell for now, my man."
Fans rushed to tweet their replies to the tribute.
One wrote: "You have set me off again Danny. You are both such an iconic soap partnership that will be so missed. Hopefully one day Robron can be reuinted.
"Wishing Ryan good luck in future adventures."
A second tweeted: "Forever iconic, forever in our hearts."
A third said: "Best partnership period! Going to miss Robron so much and thank you Ryan for five amazing years!"
Viewers know Robert was sentenced to life in prison, serving a minimum of 14 years, for the murder of Lee Posner.
Robert was set on getting revenge on the rapist after Victoria's case couldn't be taken to court, but when Lee agreed to sign over all parental rights to Vic's unborn baby, they thought it would keep him away.
However, when Lee admitted to Robert he raped Vic and hinted he would go out and do it again, Robert hit Lee over the back of the head.
Several weeks later, Lee died, more than likely as a result of the injuries Robert had inflicted.
In Friday's episode of the ITV soap (November 1 2019), Robert was told he would be moved to a prison in the Isle of Wight.
But Robert couldn't bring himself to tell Aaron the truth when he came to visit for what would be the last time.
As they were reminiscing, Robert gave his wedding ring back to his husband saying it would only get nicked.
But before he went back to his cell he broke down and made Aaron promise he'd never forget him, but didn't tell him about the prison move.
Emmerdale airs weeknights at 7pm on ITV, with an extra episode at 8pm on Thursdays.
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