The former England U23s player has signed for the Imps.
Gilliatt joins from Derby County, having spent one season with the Rams.
In the 2018-19 season, she captained Sheffield United women in their first season in the WSL. Prior to that, Gilliat made 200 appearances for Sheffield FC.
The Imps face both Derby and Sheffield FC in the coming weeks.
Gilliat hopes to help the the team push for promotion this season.
Watch her first interview as an Imp here: