Lok Sabha Speaker Somnath Chatterjee, who was expelled from the CPM two days ago for defying party directive to quit the post, turned 80 on Friday. Sonia Gandhi drove to Somnath's 20, Akbar Road residence on Friday morning to convey her birthday wishes to Chatterjee, while President Pratibha Patil and Prime Minister Manmohan Singh sent officials to extend their greetings on the occasion.