Justin Bieber sells plain white tee shirt range

Justin Bieber is selling plain white tee shirts.

The superstar singer quit his 'Purpose' world tour last month, and his latest venture since taking a break from his shows has been revealed as a fashion collaboration with stylist Karla Welch.

Justin said the line of long white designer tops, which will be sold at a pop-up shop in Los Angeles, is pushing "boundaries," according to Vogue.com.

He told the site: "Karla and I have always pushed boundaries together and this collaboration is a continuation of that."

And Karla revealed the collaboration came about when Justin approached her to buy one of her Hanes tee-shirts but was unhappy with the shape.

She said: "(Justin) wanted them tomorrowm. He was so fearless. [He

said], 'I want T-shirts that are long,' and they literally didn't

exist in the marketplace. It was a bit of a nightmare."

The news comes after it was revealed that Justin's father Jeremy Bieber flew to Los Angeles to spend some quality time with the 23-year-old star.

Jeremy, 42, who lives in Ontario, Canada, brought Justin's half-brother Jaxon, seven, and he was spotted driving around in a convertible behind the 'Never Say Never' hitmaker's vehicle.

Sources have told TMZ that Jeremy has flown over to spend some time

with his son after a tough last month in which he axed the remaining 14 dates of his 'Purpose World Tour' and accidentally hit a photographer with his car.

There had been speculation Justin may have left his tour to focus on religion, but Hillsong Church pastor Carl Lentz is not thought to have agreed with the singer's decision and advised him not to pull out of

the gigs.

A source recently said: "The church didn't tell Justin to cancel the tour."

Justin is thought to have chosen to axe the concerts to focus on "spiritual soul-searching".

The insider added: "He made his decision based on spiritual

soul-searching and his own view of the path in life he should be