Lomas was said to be in the running to play Carla Connor's long-lost brother Rob, speculation that Marsh seemed to confirm in an interview with Digital Spy.
However, the Michelle Connor actress told Soaplife: "It was one big massive rumour. Jamie's not really into joining another soap right now.
"He fancies doing something different, which is one of the reasons he left Hollyoaks. It's nice for him that there was such a buzz about it though."
Lomas, 32, starred in the Channel 4 teen soap as Warren Fox between 2006 and 2011.
Coronation Street bosses earlier this month unveiled Marc Baylis in the role of Carla's brother.
The couple's relationship was recently tested when Lomas was accused of cheating on the former Hear'Say singer.