Bruce signed Bent in a club-record £10million deal from Tottenham over the summer and the 25-year-old has made an immediate impact with eight goals in the Barclays Premier League.
Bruce told the club's official website: "Darren is a top lad with an immaculate work-rate on and off the pitch and it's a testament to his record and attitude that Mr (Fabio) Capello has decided to add him to the squad."
He added: "If you look at the number and type of goals he's scored this season, it shows what a well-rounded player he is.
"When we first signed him, I was amazed at his natural ability in front of goal and said to myself 'this lad's going to be a top player for this club, that's for sure'."
Bent was expected to be called-up for the recent World Cup qualifiers against Ukraine and Croatia but was overlooked with Capello instead plumping for the less prolific Emile Heskey, Gabriel Agbonlahor and Carlton Cole.
Bruce has revealed the snub never affected Bent's performances.
He added: "The fact he's kept going after not making other squads shows the type of lad he is - I'm absolutely over the moon for him."