Since the boy band leaped to fame in 1997, his bandmates Justin Timberlake, JC Chasez and Joey Fatone have been romantically linked to a host of female celebrities, but Bass' lovelife has remained low-key.
The New York Post newspaper reported last week that Bass and Lehmkuhl - who won the 2003 prize in the Amazing Race with his former lover Chip Arndt - were together at gay bar Atlantic House in Provincetown, Massachusetts.
He adds, "If privacy is what Lance wants, that's something that's easy to have.
But if you're Lance Bass, and you're going to the gayest town on the gayest day of the year and going to gay parties, you have to expect something." Bass' spokeswoman Cindy Owen and Lehmkuhl's spokeswoman Mara Santino have refused to comment on the Post reports.
In Here's What We'll Say: Growing Up, Coming Out, And The US Air Force Academy, Reichen Lehmkuhl claims he was sexually assaulted by straight military men after he "came out." And the 32-year-old now alleges that he and Bass have been told their lives are in danger in menacing communications they have received. Lekhmuhl adds, "Everything is being covered so we feel safe." In his book, Lekhmuhl recalls, "A bag was put over my head. I was forced to do things sexually with two other male cadets.
He tells People magazine, "I knew that I was in this popular band and I had four other guys' careers in my hand, and I knew that if I ever acted on it or even said (that I was gay), it would overpower everything. He adds, "The thing is, I'm not ashamed - that's the one thing I want to say.
I don't think it's wrong, I'm not devastated going through this.
Lehmkuhl adds, "People should be able to come out on their own.
I don't know so much that it helps gay equality if a celebrity is outed by someone else and it shows that they're forced out.