Pop singer Justin Bieber joined the Pittsburgh Steelers for prayer service before their game on Sunday, and some are blaming him for the team's unexpected loss the following day. 

The NFL team held a Bible study and prayer meeting on Saturday night, and was joined by the megastar.

Commentator and former player Terry Bradshaw called Bieber's presence a distraction. 

"Would Bieber be a disruption? Well, I wouldn't have had him there," he told TMZ Sports. 

"The only time I recall the Steelers teams I played on letting outsiders worship with us was at the Super Bowl ... and it was with our families because they traveled with us."

Bradshaw is also a devout Christian, and said that the team prayer meeting is supposed to be out the players' relationship with God. With a pop star in the room, "Your focus isn't where it should be," he explained. 

"If [Bieber] had been a part of the team from the beginning, fine... but a one-timer, no."

While the Steelers loss to the New York Jets was surprising, Bradshaw stopped short of calling the 20-year-old a curse. 

"It's automatically assumed he's a jinx," Bradshaw admitted. "That's ridiculous."

Bieber has been spotted at worship services and Bible studies regularly over the past several months. 

He was reportedly on a religious retreat with Hillsong pastor Carl Lentz last month, and attended church service and Bible study while in New York. 

The singer was also spotted crying after a Hillsong concert in California. 

In June, Bieber was reportedly baptised by Pastor Carl in a bathtub after requesting a private baptismal ceremony.

Bieber is a regular at Hillsong Church in NYC, and often shares tweets and pictures demonstrating his friendship with the pastor.