The firm was offered the work after Trilliam's usual adviser Freshfields had to withdraw because of a conflict of interests.
Lovells acts for a consortium made up of Trilliam and Land Securities. The project - London Underground Property Partnership - involves the development and management of the company's non-operational property across the entire network.
The invitations to tender closed at the end of January and the shortlist for bidders is expected to be revealed within the next two weeks.
Perry Noble, banking and project finance partner at Freshfields, says the firm is already acting for London Underground on the project.
"The decision to act on the property project was taken because we are already acting on another project, the PPP (public private partnership) project," he says.
"It was not a natural progression to act for Trilliam because it is very difficult to split the role."
However, Noble says the firm is acting for Trilliam on the Inland Revenue's Strategic Transfer of the Estate to the Private Sector (Steps) initiative