Ian McKellen is joined by Phoebe Waller-Bridge, Jeremy Irons and more at ATG's summer celebration

The ATG inaugural summer party was held at Kensington Palace's gardens in recognition of the significant contribution that actor Ian McKellen has made to the theatre and film industry. Guests included Sinead Cusack, Jeremy Irons, Denise Gough, Lynette Linton, Bonnie Langford, Iwan Rheon, Kelsey Grammer and Sonia Friedman.

McKellen's recent sold out 80-date tour of his one-man show, Ian McKellen on Stage with Tolkien, Shakespeare, Others and You – celebrating the star's 80th birthday this year – transfers to the West End's Harold Pinter Theatre from 20 September. The show has raised over £3 million for regional theatres to date and profits from the West End run will benefit an additional selection of theatre charities.

McKellen said, "Taking my new show to 80+ theatres up and down the country, has been a joyful birthday present to myself. I've played many theatres I knew well as a young theatregoer and actor and a few that were new to me. On my birthday, I was in Bolton Town Hall where my dad used to work. The tour began last February with 15 theatres in Greater London and has now ended in Orkney.

"Back in London, I'm ready for a limited season in the West End, raising much-needed funds for national theatre charities. For each performance at the Harold Pinter Theatre, I'm glad that there will be 80 tickets at just £10."