Bryan Cranston has asked fans to pray and "send positive thoughts" to Bob Odenkirk after his former Breaking Bad co-star collapsed.

The 58-year-old was taken to hospital by ambulance after falling ill on Tuesday on the New Mexico set of Breaking Bad prequel drama Better Call Saul.

It is not clear what caused the collapse.

Cranston, who starred as drugs kingpin Walter White in Breaking Bad, shared a photo of himself and Odenkirk together on Instagram.

We need your consent to load this Instagram contentWe use Instagram to manage extra content that can set cookies on your device and collect data about your activity. Please review their details and accept them to load the content.Manage Preferences

He wrote: "Today I woke up to news that has made me anxious all morning. My friend, Bob Odenkirk collapsed last night on the set of Better Call Saul.

"He is in the hospital in Albuquerque and receiving the medical attention he needs but his condition is not known to the public as yet.

"Please take a moment in your day today to think about him and send positive thoughts and prayers his way, thank you."

Aaron Paul, who starred as Jesse Pinkman in Breaking Bad, posted his own message on his Instagram page.

Beside a close-up snap of Bob, he wrote: 'I love you my friend ??.

We need your consent to load this Instagram contentWe use Instagram to manage extra content that can set cookies on your device and collect data about your activity. Please review their details and accept them to load the content.Manage Preferences

Better Call Saul has been shooting its sixth and final season, which is due to air on US network AMC next year.

Like Breaking Bad, Better Call Saul is set in and mostly shot in Albuquerque, New Mexico's largest city.

Odenkirk has been nominated for four Emmys for playing the title character, an unsuccessful lawyer named Jimmy McGill who becomes increasingly corrupt and greedy and later adopts the pseudonym Saul Goodman.

His performances on Better Call Saul have earned Odenkirk four Primetime Emmy Award nominations. His film credits include supporting roles in such films as Nebraska, The Post, and Little Women. He recently received rave reviews for his performances in the big-screen action thriller Nobody.

Odenkirk previously worked as a comedy writer for Saturday Night Live and The Ben Stiller Show.