Young Thug and singer Mariah the Scientist are hearing wedding bells after four years of dating and weathering a high-profile legal saga.

Singer Mariah the Scientist and rapper Young Thug have taken their relationship up another level.

The "Go Crazy" rapper popped the question to his longtime girlfriend on stage at his "Hometown Hero: Young Thug & Friends" benefit concert in Atlanta last night -- and it's all on video!