Users who access the service via Twitter’s iPhone and Android apps, will soon start seeing adverts, from the likes of big brands such as Starbucks, appear in their timelines.
Last year Twitter introduced sponsored tweets into the app’s search results and into the trends list.
Twitter had already put adverts on the mobile version of its site, but had yet to roll out adverts via its app in the timeline.
Users of Twitter via desktops have been seeing adverts appear in their timelines since last November.
A Twitter spokesman wrote: "In the coming weeks, we'll begin introducing Promoted Tweets in the timeline on these mobile apps. Initially, a small number of users may see Promoted Tweets near the top of their timelines from brands they already follow… Promoted Tweets will appear in your timeline like any other Tweet, and like regular tweets, they will appear in your timeline just once; as you scroll, the Promoted Tweet will flow with the rest of the Tweets in your timeline.
"As with Promoted Tweets in search, we will only display Promoted Tweets in the timeline when they are relevant. If you see a Promoted Tweet that isn’t relevant to you, you can easily dismiss it from your timeline with a single swipe."
The company launched its advertising product two years ago – but has failed to fully exploit its huge growth in users with a similarly financially successful advertising model.
More than half of its 100 million active users access Twitter via their mobile. However, promoted tweets will not appear in users’ timelines if they are accessing Twitter via a third party mobile app, such as TweetBox.
Twitter first announced promoted tweets in April 2010. At the time of launch, Biz Stone, co-founder of Twitter, summarised them as "ordinary tweets that businesses and organisations want to highlight to a wider group of users".
A poll conducted soon after the announcement found that nearly 70% of UK Twitter users were unhappy with the idea of promoted tweets.
The research, which was conducted by discount website, Groupola, and polled 1,219 UK Twitter users, found that 68 per cent of those interviewed were upset about the idea of branded tweets entering their personal feeds.