Ceawlin Thynn, 8th Marquess of Bath

On 26 October 2014, the Marchioness, then known as Viscountess Weymouth, gave birth to their first child, John Alexander Ladi Thynn. On 30 December 2016, their second child, Henry Richard Isaac Thynn, was born by surrogacy at a private clinic in West Hollywood.

In September 2013, Bradley resigned and in February 2014 American Bob Montgomery was hired for the role.

The couple's 2013 marriage was boycotted by his parents, but attended by his sister.

In November 2012, aged 38, Thynn announced his engagement to Emma McQuiston (born 1986), daughter of Suzanna McQuiston and Nigerian oil billionaire Ladi Jadesimi, a founder and the executive chairman of Lagos Deep Offshore Logistics. Emma is a much younger half-sister of Iain McQuiston (born circa 1962), husband of his half aunt, Lady Silvy Cerne Thynne (daughter of Ceawlin's paternal grandfather the 6th Marquess of Bath by his second wife).

Since June 2010, Thynn has been a director at Finmetron AB, a Swedish listed firm offering factoring services in Russia.

From 2010 until 2013, Thynn was executive chairman of Wombat's Holdings GmbH – a chain of hostels in Germany and Austria – having acquired a majority stake in the company. Wombat's hostels were voted the best in the world by customers of Hostelworld in 2006, 2007, 2008, and 2009. The company was repurchased by its former owners in 2013, leaving Thynn without any official role.

In January 2009, Thynn became chairman of Longleat Enterprises, a limited company which comprises operations at Longleat House and Safari Park on the family estate of Longleat, near Warminster in Wiltshire, as well as the commercial activities at Cheddar Gorge, in the Mendip Hills in Somerset. Following Lord Bath's retirement in 2010, Thynn hired a new chief executive, David Bradley, formerly of Legoland. Together they have worked with designers from Hollywood on improving the house and park; additions to the park include "Jungle Kingdom", "Monkey Temple", and "Hunters of the Sky".

In 2008, Thynn formed The Lion Trust, a private equity vehicle of which he is the principal. The Lion Trust invests in a range of mature and emerging markets.

In 1996, Thynn was injured in a building collapse in Paharganj, New Delhi, which killed his fiancée, Jane Kirby, and his business partner, Crinan Wilde.

Thynn is (and his father was) a trustee of the Longleat Charitable Trust, a registered charity. The trust was established in 1996 and has focused charitable activity on relieving poverty amongst people living around the Longleat Estate and Cheddar Gorge, and supporting local pensioners with their fuel bills. The trust also provides grants to local schools and churches, including the refurbishment of the village hall.

Ceawlin Henry Laszlo Thynn, 8th Marquess of Bath (/ˈ s uː ə l ɪ n / ; SOO -ə-lin; born 6 June 1974), styled Viscount Weymouth between 1992 and 2020, is a British businessman and the first son and second child of the late Alexander Thynn, 7th Marquess of Bath, and his wife, Anna Gyarmathy. He is involved in a number of companies in the leisure, tourism, real estate, and financial services sectors.