Defenders Robert Huth and Jonathan Woodgate agreed to join Middlesbrough on Wednesday, the Premier League club said.
Centre half Huth signed a five-year deal for six million pounds from English champions Chelsea while injury-plagued Woodgate agreed a one-year loan from Spanish giants Real Madrid.
"We have added two international defenders to our squad... and this is a significant coup for Middlesbrough and a big boost to everyone at the club," manager Gareth Southgate said.
"Both players feel they have a point to prove -- and the great thing is they want to do that with Middlesbrough."
Middlesbroughalso confirmed the signing of Charlton Athletic midfielder Jason Euell.
Germany defender Huth, 22,was set to join Boro in the close season but a move fell through after he failed a medical. He has been capped 17 times by Germany and played 68 times for Chelsea.
Middlesbrough-born Woodgate joined Real from Newcastle United in August 2004 for over 13million pounds but made only sporadic appearances for the club after suffering a series of injuries.
On Wednesday, the 26-year-old,capped five times by England, passed a medical at Middlesbrough and the deal includes the option for the club to sign him permanently.