Pop star Justin Bieber has come a long way since the world was introduced to the fresh-faced hitmaker only a few years ago.
In an Instagram photo posted on Wednesday, a shirtless Bieber showed off his ripped physique with the caption "Me and my trainer".
"We all want impressive chest and arms," Bieber told Newsday, during his recent tour in Asia.
His trainer, Patrick Nilsson, 29, said he wanted to bulk-up the 19-year-old's body.
"I was more excited than anything," Swedish-born Nilsson told Newsday.
"This is what every personal trainer wants - to train someone like Justin."
Nilsson has been training Bieber full-time since September 2012 and reportedly built a work-out centre inside the Canadian-born star's Southern California house.
"Whether on tour or at Bieber's home gym, the duo train together five times a week, approximately 40 minutes per session," Newsday reported.
"During their training sessions, they target mainly what Nilsson describes as 'meat and potato exercises' involving compound movements which train more than one muscle group at a time."Bieber generally performs 12 total sets per body part, four sets per exercise, with 8-12 (sometimes 12-15) repetitions per set."