Wasps have signed Saracens number eight Sione Vailanu for next season.
The 24-year-old Tonga international has only made four Premiership appearances since joining Sarries in January 2018.
England number eight Nathan Hughes is leaving Wasps in the summer after recently agreeing a deal with Bristol.
"Sione is strong, has international experience and is still very young. We can't wait to help him realise his potential in a very competitive back row," said director of rugby Dai Young.
Wasps have not disclosed the length of Vailanu's contract.
He is their second signing of the week after they announced Italy wing Matteo Minozzi will join from Zebre ahead of next season.