Singer Dua, 28, is presenting an award and Master of the Air actor Callum, 34, is a guest.
A source said: “Dua and Callum have been joined at the hip and have fallen head over heels in love.”
They began dating last month and went to the theatre in London on Friday.
Dua was also seen talking to Callum’s mum Rosemary in the capital last week.
“The Baftas is the perfect event for them to walk the red carpet together as it’s prestigious and noteworthy.
“All eyes will be on them and they’re looking forward to publicly cementing their romance.
“They’ve met each other’s families now and feel it’s serious.”
The couple went to see The Motive And The Cue at London’s Noel Coward Theatre on Friday night, starring Johnny Flynn, Callum’s co-star in 2020 movie Emma.
Houdini hitmaker Dua was also pictured embracing Callum’s mother Rosemary, in London, last week.
Speaking of his mother in 2016, who he then lived with in Chelsea, the Masters of the Air actor said: “She instilled this belief in me that if I wanted to do something, anything, I should go for it.”