Cullen, 20, has put pen to paper on a new loan contract that will keep him with the Bantams until the end of the current 2016/2017 campaign.
Wearing the club's #BantamsFamily fourth shirt, Cullen is pictured either side of club chairmen Edin Rahic (left) and Stefan Rupp (right) at the Northern Commercials Stadium after completing the necessary paperwork for the loan extension this Tuesday.
The news of Cullen's extension is a huge boost to City after a series of mightily impressive performances in midfield from the youngster, making him a firm favourite with supporters.
Since agreeing to rejoin the Bantams back in August, Cullen has played 22 times in the league for City, missing only two Sky Bet League One fixtures due to international duty with the Republic of Ireland Under 21s.
Including his spell on loan with City last season, Cullen has only tasted defeat 6 times in 37 games in League One for the Bantams.
Speaking about his extended stay at Valley Parade, Cullen said: "It was quite an easy decision for me.
"I've enjoyed playing my football here.
"Everything about the club - the staff, the players, the fans - they have all been brilliant with me both last season and this season so far.
"When it came to extending my stay once again, it was only just a case of getting everything sorted out. It was never really a decision I had to make.
"I am really pleased everything is signed now and we can kick on with the second half of the season.
"It was great to start the new year with a win (at Northampton Town). As a squad, we just want to kick on now and use that result as a boost for the rest of the month and beyond.
"The target is obviously to look towards the top of the table come the end of the season but we must take it one game at a time.
"We won't be doing it alone if we are to achieve a play-off spot or promotion, we are going to need the fans' help every step of the way. We wouldn't be where we are in the table if it wasn't for their backing.
"They were fantastic at Northampton - they have been home and away all season really.
"If they can continue that support, it will give us a great platform to hopefully do the business for the rest of the campaign."