The package-tour operator will adopt a direct and online strategy, primarily targeting its existing customer database.
The activity will include a series of monthly mailings, which will differ according to the holiday destinations the recipient has booked through Thomson in the past.
The drive, which is scheduled to begin later this year, will be supported by an online and email campaign created in-house.
WDMP won the business following a four-way pitch overseen by Thomson Holidays' head of CRM, Phillip James. The account had previously been handled by Bright, which repitched for the work.
Thomson is one of the biggest spenders on direct activity in the package operator sector. According to Nielsen Media Research, it invests more than £19m on promotional activity in the UK across its sub-brands, which include Portland Direct.
Last month, parent company TUI began a review of the £15m UK advertising account for its Thomsonfly and Thomson brands. The pitch, which is being over-seen by Agency Assessments International, will include incumbent DDB London.
Thomson's media business, handled by Media Planning Group, is not affected.
Earlier this year, Thomson sales and marketing director Miles Morgan left the company following a management restructure. His duties were handed to commercial director David Burling.
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