Hours after "Bad Romance" singer's post, Mars, 38, shared a photo on his Instagram account of him wearing a Lady Gaga t-shirt. The coordinating posts are fueling rumors that a collaboration ...

Lady Gaga debuted a brunette hair transformation via Instagram. The singer also wore a Bruno Mars t-shirt, which fans think is a hint at a collab between the two artists.

Hours after "Bad Romance" singer's post, Mars, 38, shared a photo on his Instagram account of him wearing a Lady Gaga t-shirt. The coordinating posts are fueling rumors that a collaboration ...