The 18-year-old, who netted 33 goals in 30 games for the youth and reserve teams last campaign, has been used regularly by Tigers boss Nigel Pearson this season having made 13 appearances.
And, despite his only goal coming in August's Carling Cup defeat to Brentford, Cullen is confident he can repay Pearson's faith.
"I haven't scored many goals, which is a concern, but I've got to keep working hard and I'm sure they'll come," Cullen told Hull Daily Mail.
"It's not something that plays on my mind. I've got good confidence in myself that if I get an opportunity, I'll still put it away.
"You can never doubt yourself - I know I can score goals, as I showed last season, and I haven't lost any belief."
Source: PA
Source: PA