The 24-year-old 'Bleeding Love’ singer is planning to go into the studio with the 'Angels’ hitmaker this month, and the pair hope to record more than one song together.
A source said: "Leona is incredibly proactive. She knows exactly what she wants and where she's heading and is thrilled with these developments. She loves Robbie and thinks he's a real laugh – and the love-in is mutual.
"They're just going to go in the studio and see what comes out.'
Leona’s mentor Simon Cowell is said to be particularly delighted with the collaboration as he thinks it will help convince Robbie to agree to appear as a judge on his UK TV talent contest 'The X Factor’.
The source added to the Daily Mirror newspaper: 'The track will coincide with her arena tour, with the possibility that Robbie could appear on stage. Simon is really keen on the idea and hopes it will help Robbie come on board with the 'X Factor'."
Leona has also reportedly been in touch with Kings of Leon frontman Caleb Followill about a one-off track after learning the 'Sex on Fire’ rockers had been enjoying her music.
The source said: "The collaboration came about through Leona herself. Caleb and the guys are huge fans."