Madonna, 55, and 26-year-old Timor have been romantically involved for around six months now. Fans were first alerted to the singer's new relationship when she posted pictures from her New Year skiing break.
One candid family snap showed backing dancer Timor playing around on the slopes with Madonna's son Rocco, 13, and friends. The mum-of-four captioned the picture, "Bromance on the Swiss Alps! Love is in the air #happinness."
The couple are thought to have first met when they collaborated on a dance project last year; Stefan is an accomplished dancer, who performed with Beyoncé at the 2010 Grammys.
It would not be the first time that Madonna has found love through her line of work.
In December she split from French dancer Brahim Zaibat, 25, after three years of dating. Before that dated Brazilian model and DJ Jesus Luz, whom she met on a photoshoot.
Two years ago, Madonna opened up about her romance with Brahim.
"I didn't choose to, you know, I didn't write down on a piece of paper, 'I'm going to have a relationship with a younger man," said the star, who was married to Guy Ritchie from 2000 until 2008.
"I don't want to live my life on my own. I love being a mother. My children fill me up in many ways, and inspire my in many ways, but I need a partner in my life and I think most people feel that way.
"I've never really lived a conventional life, so I think it's quite foolish for me or anyone else to start thinking that I am going to start making conventional choices."