The 'Rock of Ages' actor has deleted the 'Part of Me' hitmaker from his social networking account four-and-a-half months after filing for divorce from the brunette beauty, who ditched him on twitter almost immediately after they split in December 2011, bringing an end to their 14-month marriage.
The 36-year-old comedian - who goes by the handle @rustyrockets on the micro-blogging site and regularly tweets his 4.6 million followers - axed Katy from his follower list earlier this week, shortly after he was said to have emailed the 27-year-old star asking for a second chance at their relationship.
Russell - who follows 77 people on twitter - is thought to have acted after seeing photographs of the pop star being affectionate with Florence + the Machine guitarist Robert Ackroyd, who she is rumoured to be dating, at the Coachella Music Festival.
Despite being unfollowed by Russell, Katy still has more than 19.5 million followers on the micro-blogging site, and she tracks just 88 people's thoughts.
Russell has dated a number of women since announcing his divorce from Katy, and he was recently linked to David Hasselhoff's ex-girlfriend Anouska de Georgiou.
The 'Get Him to the Greek' star was introduced to the budding actress - who dated the 'Baywatch' actor in 2010 - at a charity fundraiser in Los Angeles last month.