Sunderland have confirmed the arrival of Paddy McNair and Donald Love from Manchester United for a combined fee of £5.5m.
The United duo had been closing in on a switch to the Stadium of Light over the past week, where they will link up with former boss David Moyes.
McNair and Love, both aged 21, have penned four-year deals with the Black Cats and become Moyes's second and third signings since taking over from Sam Allardyce last month.
"Paddy is a young, athletic player who is improving all the time," Moyes told the club's official website. "He has experience for Northern Ireland and we want to bring as many international players to the club as we can.
"Donald comes highly recommended and is another young player who I hope can develop and improve here. I want to add some young players to the squad as well as some senior players and both of them have got really good potential and the opportunity to improve.
"I want to bring in players who are here for the long-term as well as the short and hopefully these two are here for the long-term."
McNair can operate both in defence or midfield and boasts two years of experience at Premier League level, while equally-versatile Love can be fielded at full-back or in midfield.
Sunderland's only other arrival this summer came last week when Papy Djilobodji joined in an £8m move from Chelsea.
Daniel Lewis
