The singer starred as Warner Huntington III opposite Smith's Elle Woods in the production at the Savoy Theatre for six months until June this year.
Quizzed about his current love life, James told Heat: "I'm single, but I'm not interested right now. I'm all work, work, work. It's a bit boring, actually.
"There's nobody I've met that... But maybe when I'm back on the road with Blue I'll get the opportunity to meet someone.
"I don't even go out. Friends come over and I cook. I see Sheridan Smith a lot - we've become so close. Our mums want us to get married."
Asked if that might ever happen, he replied: "Never say never. You never know. She's amazing. I miss her terribly now I'm not in Legally Blonde. We were inseparable when I was in the show.
"I think she's very gorgeous and very sexy. She's got a swagger, a ghetto side that I love. I always slipped my tongue in when we kissed on stage, and so did she."
When he was asked if they ever kissed off-stage, James said: "I'm not disclosing anything... We used to have a cheeky drunken snog, yes."