Approved by the Secretary of State for Digital, Culture, Media and Sport Oliver Dowden, the reappointments will see Baillie and Seddon continue to serve as commissioner until at least 10 April 2022.
Baillie is a former partner of KPMG and was most recently chair of the Accounts Commission for Scotland, having also been a member of the reporting panel of the UK Competition and Markets Authority.
Seddon spent 20 years as a filmmaker before taking up public non-executive roles. She currently sits on the Legal Services Board, where she chairs its audit and risk assurance committee.
The double reappointment comes after John Whittingdale, the Minister for Media and Data in the Department for Digital, Culture, Media and Sport (DCMS), this week took on the brief for lotteries and gambling.
Taking over from Nigel Huddleston, Whittingdale will now oversee the Gambling Act review.
Whittingdale adds lotteries and gambling to a number of other responsibilities, including the media, EU and international strategy including approach to future trade deals, overall approach to union policy issues, data and the National Archives, and public appointments, among others.