According to E! News the deal is for three years with a source close to the actor saying: "Rob likes the brand."
If the deal goes ahead, Robert will be following in the footsteps of his on and off screen lover Kristen Stewart, who is the face of Balenciaga fragrances.
Speaking about her relationship with the Spanish design house, she previously said: "Balenciaga has always stood out to me.
Even when I first began to consider fashion and admittedly rarely knew the brand I was wearing, I always knew and loved Balenciaga. It feels full circle to be involved with something that spoke to me then and of course continues to excite me now. The brand is just cool. That's the way it is."
Creative director of the brand Nicolas Ghesquiere insisted Kristen was great for Balenciaga because of her "progressive character".
He said: "Kristen embodies the modernity of the new Balenciaga fragrance with her unique sensibility and intelligence.
"From her early appearance in 'Panic Room' to her independent choice of 'Welcome to the Rileys', I've always sensed her progressive character."