The police in West Yorkshire say the men, 23 and 39 years old, were arrested in the prison suspected of involvement in the murder plans.
They will be questioned and then returned to the prison while the investigation continues, according to the police.
Extensive investigations are still ongoing in connection with the murder of Ian Watkins and these arrests are part of that, said Detective Inspector James Entwistle, according to BBC.
The former Lostprophets singer, who was serving a 29-year sentence for sexual abuse of children, died after being attacked at the high-security prison on October 11. Two men, 25 and 43 years old, have already been arrested, suspected of murder.
Ian Watkins had been serving a 29-year sentence since 2013 for sexual abuse of children, including the rape of an infant. In 2017, it was revealed that he had tried to groom a new victim from outside the prison and in 2019, his prison sentence was extended after he hid a mobile phone in his rectum.
Watkins has been attacked by other prisoners on several occasions during his time in prison.
