B.B.
My son did the same thing just before 3 years old. The first few times it happened we went in his room, but then we just stopped as soon as we realized it was becoming a pattern. It took 2 nights, the first he cried for about 10-12 minutes and then stopped and went back to sleep. The second night it was less than 3 minutes and he was back out. Now it rarely happens.
My daughter work up this morning at around 4:15 - she's 23 months old. I was going to go check on her, but my hubby told me to stay in bed and give her a minute. Less than a minute later she was back to sleep.
Good Luck!