The three-month contract follows on from his role in its 25th anniversary show of Les Miserables at London's O2 arena last October.
Lucas will play innkeeper Thernadier from 23 June to 10 September and will be joined in the show by tenor Alfie Boe, who will play the lead role of Jean Valjean from 23 June to 26 November.
Alfie Boe and Matt Lucas joined producer Sir Cameron Mackintosh on Wednesday outside the Queens Theatre in London to unveil a plaque commemorating Les Miserables as the longest-running musical in London's West End.
The show, currently performing at the Queen's Theatre, was originally staged at the Barbican before moving to the Palace Theatre.
Les Miserables won three trophies at the What's On Stage awards this week - two for the O2 concert and one for a one-off anniversary production at the Barbican.