Mogens Tholstrup, the playboy socialite who has been seen stepping out with a string of glamorous girlfriends on his arm, has made pounds 5.5m from selling the restaurants.
Belgo, in which Mr Johnson has a large stake bought from the fortune he made at the helm of Pizza Express, is paying a total of pounds 9.3m for the 37-year-old Dane's empire of eateries.
The jewel in the crown is Daphne's, the South Kensington restaurant famous for attracting ladies who lunch and It Girls.
Mr Tholstrup has also sold the nearby Pasha restaurant, whose Moroccan food has proved a hit with sophisticated Chelsea diners, and The Collection, where customers parade down a 100ft catwalk to reach their plates of sushi.
A former furniture designer and photographer, Mr Tholstrup hit London's social scene with a passion in the late 1980s. He set up his first restaurant, Est, in Soho with the help of a loan from his father. In 1991 he saved Daphne's, a former favourite of film legends such as Sir Laurence Olivier and Alec Guinness, from collapse. After splitting up from his wife Paulo Schlansen, he has dated a succession of beautiful women.
Mr Tholstrup has pocketed pounds 3m in cash and pounds 2.5m worth of Belgo shares. He will earn pounds 70,000 a year and be entitled to a bonus as managing director of Signature, a newly created subsidiary of Belgo which will oversee the expansion of the upmarket chain into new areas of London.
He has also been granted over a million share options, which would entitle him to large gains if Belgo's share price took off. Belgo is raising pounds 7.1m via a share placing to fund the deal.