The 37-year-old comedian, who recently split from Katy Perry, expressed his feelings for Halliwell at the Olympics finale, reported Daily Star.
"I've got a crush on Geri Halliwell. Everything in the world is how it should be," he said.
According to a source the pair have been texting and meeting up since they both performed at the closing ceremony for the Games.
The funnyman is said to have had a soft spot for the pop star since her 90s heyday and is wasting no time in pursuing her.
"Geri is a sucker for Russell's humour and they've been having a lot of fun together," a source said.