The Sheffield Wednesday and the Crystal Palace strikers played together at Sunderland.
Fletcher recently joined Wednesday in the summer transfer window following his release from Premier League club Sunderland at the end of the 2015-16 season.
Wickham, who is 23 years of age and can play as a striker or as a winger, is on the books of Premier League outfit Crystal Palace at the moment.
The former England Under-21 international played with Fletcher at Sunderland, and he has wished the Scotland international striker the best of luck at Championship side Wednesday.
Wickham had two loan spells at the Owls, and he seems to have spoken highly of the Championship club.
“Connor came here on loan a few years ago and he had nothing but good things to say about the place,” Fletcher told The Star.
“He actually dropped me a text the other day to say congratulations on the move. I’m a different kind of player to Connor but hopefully I can help the team build on what they did last year. That’s the plan.”
Fletcher scored four goals and created eight chances in 16 Premier League appearances for Sunderland last season before joining Marseille on loan in the January transfer window.
The 29-year-old former Hibernian and Wolverhampton Wanderers striker scored two goals and created 16 chances in 12 Ligue 1 matches for Marseille.
Wednesday enjoyed a great 2015-16 campaign and reached the Championship playoff final, which they lost 1-0 to Hull City at the Wembley Stadium in London.