Millwall have signed George Saville from Wolves along with Jed Wallace.
The Camberley-born Saville, 24, previously had two spells on loan at The Den.
Saville, who has also been on loan at Brentford, started his career at Chelsea and did not make a first-team appearance for the Blues before being snapped up by Wolves in 2014.
He has joined the Lions on a three-year contract for an undisclosed fee, as has Wallace.
“I’m very happy and really looking forward to getting going,” Saville told Millwall’s website.
“The manager wanted me in for the first day of pre-season and that makes everything easier for me and the boys.
“I’m delighted to be back down south. I know a few of the boys already – it’s a good club with good staff. There’s a buzz around the training ground following promotion – everyone is confident and excited to get going again.”
Millwall manager Neil Harris said: “I’m really pleased. George is well-known to us as he has been here as a player before. He had a really successful loan with us and we’ve monitored him ever since.
“We like to bring in players that know us and that we know and as soon as we knew of George’s availability, it was a no-brainer.
“He’s another player of a good age with really good potential. He played almost 30 games in the Championship last season, too, so he has experience.”