Photo of smiling Muamba on Twitter

Published Mar. 30, 2012 1:00 a.m. ET

foxsports

A new photo of Fabrice Muamba appeared on the midfielder's Twitter account on Friday showing him sitting up and smiling, almost two weeks after his heart stopped beating and he collapsed during the FA Cup quarterfinals.

The first photo of Muamba since his cardiac arrest showed the usually clean-shaven Bolton player bearded, fully dressed and seated with a pillow for support.

An accompanying message said: ''Fab wanted me to post this pic for you all and to also say thank you for such overwhelming support.''

The former England Under-21 international has been in London Chest Hospital since collapsing on March 17 in the game against Tottenham. Medics worked on Muamba for 78 minutes to get his heart beating.

He left his bed and began eating again this week.

Andrew Deaner, the cardiologist who left his seat among supporters at White Hart Lane to help medics treat Muamba, has called Muamba's surprisingly strong recovery ''miraculous.''

Even so, his father and fiancee released a statement last week saying he faces a long recovery and it is still unclear whether he will ever be able to play professionally again.

The quarterfinal was abandoned just before halftime and replayed this week, with Tottenham progressing 3-1.

Players across Europe have worn T-shirts expressing their support for Muamba.

European champion Barcelona was among the sympathetic clubs, while FIFA President Sepp Blatter has spoken with Bolton's chairman and asked to be kept informed of Muamba's progress.

The cause of the cardiac arrest has not been discovered. Doctors said Muamba underwent a routine screening for heart defects in August. He was checked again in the hospital and the test produced a normal result.