The 'Dear Darlin' hitmaker is determined to get the Take That pair on board for his fourth studio collection - which he is set to start working on later this year - and is already considering ways to get them both penning tracks with him.
Speaking to the Daily Star newspaper, he said: ''I'm going to write a song with Gary, we've been speaking about it for years but it will happen for the next album.
''I saw him at a party and pulled him to one side and said, 'Let's get in the studio and see what happens.'
''We want to get Robbie in too, maybe even both of them at the same time to write a song, that would be great.''
The 29-year-old singer - who is currently supporting Robbie on his 'Take The Crown' European stadium tour - insists the 'Candy' hitmaker's positive energy and good advice could help him make the best album he's ever done to date.
He explained: ''There's something on the cards. I've learned so much from Robbie, he's been great to me. I like to in a studio with guys and vibe of their energy.
''My forth album could be my Thriller, the big one. I'm close to four million albums sold across the world. The fourth could tip me over.''