Normal People stars Paul Mescal and Daisy Edgar-Jones are among the stars going head-to-head to play video game Mario Kart 8 for an online charity event.
The duo have become breakout stars following the BBC adaptation of Sally Rooney's hit novel, which explores mental health in young people.
They will be joined by musician Tom Grennan, comedians Jon Richardson, Iain Stirling and Seann Walsh, sports stars Tyrone Mings and Anthony Watson, and Strictly Come Dancing star Joe Sugg to compete on Nintendo Switch for the CALM Lock-In: Mario Kart Edition on Tuesday evening.
Fans will be able to tune in to watch the races, organised by mental health charity CALM (Campaign Against Living Miserably) on Instagram Live and Twitch as part of Mental Health Awareness Week.
The special event will feature hours of free entertainment to raise money through donations to support the running of CALM helpline services which are currently experiencing record demand.
Each famous face will go live on their own Instagram channels, while comedian Amelia Dimoldenberg will offer commentary on the games on CALM's official Twitch.
The CALM helpline has experienced record demand with more than 19,000 calls and webchats since lockdown was introduced on March 23, and says it has directly prevented 80 suicides.
Simon Gunning, CEO of CALM said: "Over the last few weeks, we've seen people need CALM and our services more than ever before.
"We know that lockdown has been incredibly tough, so we wanted to do something that would give people a fun evening and help take their mind off everything else that's happening at the moment – even if just for a few moments – whilst also raising awareness of the CALM services that can be an added support when life gets tough.
"CALM is here for anyone who needs help and our free and confidential helpline and webchat are open seven days a week from 5pm-midnight. If anyone is struggling and would like some help visit thecalmzone.net for ways to support yourself and others."
The full schedule of players is available on CALM's Instagram page at @calmzone.