Malaysia airlines lounge guest

I am travelling first class from LHR to KL on Malaysia Airlines and a friend is travelling at the same time on SIA - can he come into the lounge with me as my guest?

Thanks!

Their "card" programs (Gold and Platinum) show guests are only allowed if travelling on the same flights. So although not quite the answer to the question I would have thought it unlikely that First got you any greater guesting benefit.

This might help, "departing passengers" is the key phrase methinks.

One thing is that MH fly from Terminal 4 and SQ fly from Terminal 3 - not going to be possible.