When Christina Ruggeri asked for Red Sox outifelder Jacoby Ellsbury’s autograph at Taco Bell yesterday, she wanted to make sure no lettuce was hanging out of her mouth after taking a bite from her free taco – courtesy of the speedy rookie.

An impromptu signing session proved to be a surprising scenario for thousands of fans waiting in line at the Taco Bell beneath Warren Towers when Ellsbury, who stole second base in Game 2 of the World Series, made an appearance at 3:45 p.m. to pick up his meal.

Ellsbury, who entered through the parking garage to get his free taco and sign Red Sox memorabilia, won fans the free taco promotion when he swiped the base.

“He came in, he got his taco, said he loves Taco Bell and we said we’d love to have him come,” said Dan Benson, the head of the Taco Bell branch. “This was the closest [Taco Bell] on his route back to the stadium.”

While some people knew Ellsbury would be appearing at the taco joint, others only expected to get a free treat.

Aiden Belanger, 8, who came from Woonsocket, R.I., for yesterday’s championship parade said he was excited to have his favorite ballplayer sign his Red Sox program.

“I wanted Taco Bell,” said Wentworth Institute of Technology sophomore Pete Olbrys. “I didn’t even know what’s-his-name was going to be here.”

Benson said Taco Bell decided on the promotion because of the livelihood of a player stealing a base in at least four games of the World Series.

“We said, ‘Hey, why not,’ steal a base, steal a taco,” Benson said. “It certainly happened a little quicker than we thought.”

Despite the large crowd gathered outside Taco Bell, fans were relatively calm.

“Not only were [customers] . . . polite, but we had fans cleaning the store for us,” Benson said. “They kept clear and made an aisle for Ellsbury to walk through. [We] couldn’t have asked for a better group.”

Christine Cassis contributed reporting for this article.