The firm, which sells more than 50 million cups of coffee each year, announced it will serve takeaway hot drinks at its 950 pubs.
Chief executive John Hutson said: “Our coffee is extremely popular with customers.
“We sell around a million cups a week in our pubs across the UK, and believe customers will welcome the opportunity to enjoy a takeaway cup too, at 99p.”
The move will see the pub giant go head-to-head in a high street battle taking on the likes of Starbucks and Costa.