The Spain Under-21 goalkeeper wants to see his international team-mate make the move to Old Trafford this summer, although he has acknowledged a transfer could be problematic
The Premier League giants are keen to add some fresh blood to their midfield this summer and have made Thiago one of their primary targets on the transfer market.
"Hopefully I will have a Spanish team-mate at United next season. I, and every other Manchester United player, would like him to join the club," De Gea was quoted as saying by El Mundo Deportivo.
"We have been joking about him joining United. Barcelona will realise that they have a great player, though, and I don't think they will let him go."
The Spain international has a contract with Barcelona until the summer of 2015, but the failure to participate for a stipulated amount of minutes in 2012-13 has seen his exit clause plummet from €90 million to an attractive €18m.
However, his minimum fee release clause returns to €90m on August 1.
Thiago is a product of the Barcelona youth academy and has made over 100 official appearances for the Catalans since making his first team debut in 2008-09.