The Aston Villa-owned midfielder is pleased for his Nottingham Forest teammate.
Vaughan has told BBC Radio Nottingham that he has signed a one-year contract extension.
Gardner, who joined Forest from Premier League side Aston Villa on loan in the January transfer window, is happy for the 33-year-old.
Vaughan has scored one goal and created 33 chances in 29 Championship appearances for Forest so far this season.
The 33-year-old midfielder has a pass accuracy 85% and a shot accuracy of 14%, and has won 19 headers, 14 dribbles and 93 tackles.
Meanwhile, Gardner has created five chances in nine Championship matches for the Reds so far this campaign.
The 23-year-old midfielder has a pass accuracy of 83% and a shot accuracy of 25%, and has won 21 headers, three dribbles and 13 tackles.
Forest are 13th in the Championship table at the moment with 45 points from 35 matches.