His remit is to drive the venue’s non-match day business by targeting senior event buyers in the UK and overseas.
Mills joins from Visit Britain, where he was made redundant from his role as head of business visits and partner marketing in March.
TEL managing director Chris Morris said: "Simon is a respected senior marketer in the industry who will drive our business and help us realise the full potential of the facilities at Twickenham Stadium."
Twickenham Stadium’s conference centre has 5,000sqm of integrated space including a auditorium for 450 delegates. The venue’s event suites have capacity for between ten and 850.
Former business development manager Nick Kenton left the stadium to join Lord's as its new meetings and events sales manager in April.