The 26-year-old, who left Rangers in the summer of 2007 but failed to make a single appearance during an injury-hit season at Craven Cottage, has signed a three-and-a-half-year contract.

Cook returned to Loftus Road on loan at the start of this season and has made 26 appearances, scoring one goal.

"Everyone knows QPR are my club and I'm delighted to be back here. The club are really going places and I'm just delighted to be part of what we hope will be a very successful chapter in its history," he told Rangers' official website. "I feel as though I am getting back to my best and I can't wait for the second half of the season."

Rangers boss Paulo Sousa added: "Lee is an integral part of our future plans and we are delighted to have him here on a permanent contract.

"He's proven at this level, has great quality and gives us excellent options in the attacking third of the pitch."