Shatner will co-star with a computer in the new ads, touting the name-your-own-price service.
The former "Star Trek" star renewed his contract with Priceline earlier this year for both radio and television ads. Financial terms of the relationship were not released.
Shatner was replaced as Priceline pitchperson by "Sex and the City" star Sarah Jessica Parker for a while last year. Shatner, who had initially received stock in the company as payment, saw his investmentalong with Priceline's stock.
Shatner said that his relationship with Priceline had broadened "from a celebrity spokesman to a customer who has enjoyed the significant savings and benefits of Priceline.com."