The Coronation Street is reportedly "very keen" on the St Helens forward, and the pair have been spotted together at a mutual friend's party.
"Michelle and Mark really hit it off," a friend told The Mirror. "They've been texting quite a bit, teasing and flirting with each other, and they're planning to get together again soon.
"Michelle is a fan of rugby league and he's definitely her type. It's early days, but watch this space."
The friend also spoke of a possible "awkwardness" between the pair, as Keegan was once linked with Flanagan's teammate Jon Wilkin.
Keegan split from The Wanted's Max George in July, after calling off their engagement six months previously.
The actress was also spotted with ex-boyfriend Brad Howard last month.