Facebook has announced plans to launch video ads that will automatically appear on users' timelines for up to 15 seconds and without sound.

According to the Wall Street Journal, the new ads will begin to appear on the web and on mobile devices Thursday. The new ads have been planned since August with various advertisers urging the social networking giant to launch them ahead of the holiday season.

Facebook reportedly held strong and waited until closer to Christmas to officially launch the video ads in fear of annoying too many of its users. Some advertisers have had videos ready to go since the summer, while others are afraid to alienate current and prospective customers with what can essentially be considered pop-up videos.

Mark Zuckerberg told the WSJ previously he took a personal interest in the video ads and held their launch back because they were slow to load. Last week, some Facebook users got the first look at the video ads as they were being tested out.

Fees for video ads are likely to be pricey, given their placement in users' news feed and the sheer volume of users on Facebook.

"We do not disclose pricing," Facebook said in a written statement Tuesday. "The goal for this test feature is to be a premium advertising format on Facebook, intended to reach a large audience at specific times."

However, some executives told the WSJ in August they estimated Facebook would sell video ads for $2 million per day to allow advertisers access to adults ages 18-54, the social networking site's primary audience.

"In terms of monetization, the video ads are very important," Colin Sebastian, an analyst for Robert Baird & Co, told Reuters. "They're priced a lot higher than traditional display or text ads. And it also opens up for Facebook a larger group of advertisers."

Facebook is likely anticipating a great success rate for the video ads. Since launching auto-playing (minus sound) for user-uploaded videos, views, shares, likes and comments have risen ten percent.