The Germany Under-19 international, who signed his first professional contract last summer, has put pen to paper on a deal until June 2013.
Selected to travel with the first-team squad for the recent game at Championship leaders QPR, Schlupp was named in the matchday squad for the first time against Norwich last week.
After signing his new deal, Schlupp immediately joined Brentford on a one-month loan. He will link up with fellow Fox Robbie Neilson on loan at the League One club.
Source: PA
Source: PA