ASHBURN, Va. - Clinton Portis was back in costume Thursday, colorfully dressed as a dance instructor named “Choo-Choo.”

The Washington Redskins running back wore an orange shirt with sequined and ruffled red, orange and yellow sleeves. Around his neck was a long orange scarf decorated with a huge safety pin. On his head was a black wig with a huge bun on top. He looked into cameras through oversized blue-tinted glasses with lavender frames — with a $9.99 price tag still attached.

It’s amazing what a slump-ending 196-yard game will do.

“It’s a message for the Washington Redskins to go out there and have fun,” said Portis, his voice raised an octave or two. “When you have fun, you win.”

It was Portis’ first costumed appearance of the season, and it evoked memories of his weekly cast of characters — including “Southeast Jerome,” “Sheriff Gonna Getcha,” and “Dolla Bill” — from the Redskins’ playoff run of 2005. Teammates were beginning to wonder if Portis’ days in dress-up were over, and the stunned looked on their faces was priceless when they saw Choo-Choo holding court at the back door of Redskins Park following Thursday’s practice.

“He’s back!” called out quarterback Jason Campbell.

“You scared me, boy!” said cornerback Shawn Springs.

Portis has spent the past 12 months striking a more aloof tone with reporters, having been stung by criticism that he might not be the back he once was. He endured several injuries last year, played in only eight games and ran for a career-low 523 yards. He donned a costume only once, playing a character called “Dolomite Jenkins.”

A knee injury kept Portis out for all of this season’s training camp, and he had a career-high drought of 12 games without rushing for 100 yards before the 196-yard outburst in last week’s win over the New York Jets.

Asked if it took a big game for the costumes to return, “Choo-Choo” answered: “It took 196 yards to give me hope that I could teach the boy how to dance.”

Choo-Choo, who said he got his hair done by Paris Hilton’s hairdresser, said he’s also been teaching dance moves to several other players to help them with their end zone celebrations.

“I’m here to teach the boys how to celebrate,” he said.

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Choo-Choo eventually lowered his voice and spoke as Portis, saying that his body has responded well from his 36 carries against the Jets. He also acknowledged the psychological boost his big game had given the team. The player who became the face of the franchise two years ago was back, in more ways that one.

“To have that game, to get out of the slump that I was in, was a great opportunity,” Portis said. “I think it was great for the team. I think it was great for the offensive line. Now that we see we can do it, there’s an opportunity that we can do it more.”

Asked if there will be another costume next week, Portis’ voice again became Choo-Choo’s.

“I can’t predict next week,” he said. “One day at a time. You’re putting too much strain on Choo-Choo. You calm down.”