by Richard Huff
Kellie Martin, the actress who first won viewers' hearts almost a decade ago in Life Goes On is having a very good year. First, she landed a big-time gig playing a med student in the NBC megahit ER. Then, last week, she got engaged. And it was so romantic, with boyfriend Keith Christian, a Columbia Law School student, proposing while the two were touring the Metropolitan Museum of Art. "He pulled out this little box and I said yes before he could ask the question," Martin told The News yesterday. Martin expects to tie the knot by the end of next year. "I don't want to wait," she said. "I want that dress. I can't wait to get a wedding dress." Martin is in New York this week enjoying a rest from the fast-paced ER and to talk about "Hollywood's Greatest Christmas Moments," a holiday film-clips special she's hosting on the upstart Pax Network (Dec. 15, 9 p.m.). "Pax airs Life Goes On and Christy [Martin's followup series] all the time," she said. "I don't watch TV much, but whenever I turn the TV on, I see my face. Life Goes On was my favorite thing." Not that her current show is taking a back seat, mind you. "ER is the greatest job in the world, in so many ways," she said. "It's well-written, it's well-directed. The camera work is just the tops. It's really exciting to be working in the top of television." When she said yes to joining ER; she didn't even know what her role was. When the script for the season opener arrived, she was blown away to see that her character, Lucy Knight, was in virtually every scene. "It was basically, 'Here you go, Kellie, let's see if you can handle this job,'"; she said. "I just talked myself into pretending not to care." She pulled it off, and Lucy has remained front-burner since. "I am so happily surprised," she said.