"The show is now joined by Shilpa Shetty. She looked lovely as always and very trim. She displayed mock anger at meeting me because I missed wishing her on her birthday. Horrible me, " Amitabh posted on his blog www.bigb.bigadda.com.
Shilpa joined the Bachchans in London Saturday for the last leg of their Unforgettable tour.
Amitabh wrote that due to his "frequent travel and odd timings", he forgot the actress's birthday, which was on June 8.
Amitabh also revealed that Shilpa believes that every year that he wishes her, "her year goes off successfully".
"I wish it goes off even better this year, though I must remember not to miss it again, " he wrote.