The 'Rock DJ' singer made the confession on his official blog, where he also posted the music video for Gallagher's new single 'The Death Of You And Me'.
Williams said: "I know it's pretty redundant, but I'd love to write with him."
According to The Mirror, the Take That star also sent the former Oasis guitarist an email.
"He would love to hang out with Noel... but writing together seems a long way off," a source said.
However, recent reports said that Williams told the crowd at Take That's Wembley Stadium show that Gallagher could "lick [his] arse".
> Robbie Williams ends feud with Noel Gallagher?
Watch the music video for 'The Death Of You And Me' by Noel Gallagher's High Flying Birds below: